Fix where to create temporary files

[yamamoto-febc]

(from @mkozjak's comment, thank you @mkozjak!)

This PR fixes to where to create temporary files.

Motivation/Background

The expected behavior of creating temporary files is as follows:

• RKE provider make temporary directory in current directory with random name.
• While running RKE provider, cluster.yml and kube_config_cluster.yml is generated into the temporary directory.
• After running RKE provider, the temporary directory is cleaned up.

However, current provider doesn't work well.

This unexpected behavior is based on to bad calling to following RKE's function:

https://github.com/rancher/rke/blob/v0.1.15/pki/util.go#L278-L286

Function pki.GetLocalKubeConfig has two arguments.
The function changes the behavior depending on whether there is a slash at the end of the second argument.

If args are (cluster.yml, /foo/bar/), the function returns /foo/bar/kube_config_cluster.yml.
If args are (cluster.yml, /foo/bar), the function returns /foo/kube_config_cluster.yml.

This is very confusing.

So I decided don't use second argument, always specify "".

Acceptance test results:

$ make testacc
TF_ACC=1 go test ./... -v  -timeout 240m ; \

?   	github.com/yamamoto-febc/terraform-provider-rke	[no test files]
=== RUN   TestAccRKENodesConfDataSource
--- PASS: TestAccRKENodesConfDataSource (0.02s)
=== RUN   TestProvider
--- PASS: TestProvider (0.00s)
=== RUN   TestProvider_impl
--- PASS: TestProvider_impl (0.00s)
=== RUN   TestAccResourceRKECluster
--- PASS: TestAccResourceRKECluster (205.13s)
=== RUN   TestAccResourceRKECluster_NodeCountUpAndDown
--- PASS: TestAccResourceRKECluster_NodeCountUpAndDown (345.66s)
=== RUN   TestAccResourceRKEClusterWithNodeParameter
--- PASS: TestAccResourceRKEClusterWithNodeParameter (150.11s)
=== RUN   TestParseResourceRKEConfigNode
=== RUN   TestParseResourceRKEConfigNode/minimum_fields
=== RUN   TestParseResourceRKEConfigNode/with_both_role_and_roles
=== RUN   TestParseResourceRKEConfigNode/without_both_role_and_roles
=== RUN   TestParseResourceRKEConfigNode/invalid_role
=== RUN   TestParseResourceRKEConfigNode/invalid_roles
=== RUN   TestParseResourceRKEConfigNode/use_roles_attr
=== RUN   TestParseResourceRKEConfigNode/all_fields
--- PASS: TestParseResourceRKEConfigNode (0.00s)
    --- PASS: TestParseResourceRKEConfigNode/minimum_fields (0.00s)
    --- PASS: TestParseResourceRKEConfigNode/with_both_role_and_roles (0.00s)
    --- PASS: TestParseResourceRKEConfigNode/without_both_role_and_roles (0.00s)
    --- PASS: TestParseResourceRKEConfigNode/invalid_role (0.00s)
    --- PASS: TestParseResourceRKEConfigNode/invalid_roles (0.00s)
    --- PASS: TestParseResourceRKEConfigNode/use_roles_attr (0.00s)
    --- PASS: TestParseResourceRKEConfigNode/all_fields (0.00s)
=== RUN   TestParseResourceRKEConfigNodesConf
=== RUN   TestParseResourceRKEConfigNodesConf/JSON
=== RUN   TestParseResourceRKEConfigNodesConf/YAML
=== RUN   TestParseResourceRKEConfigNodesConf/both_JSON_and_YAML
--- PASS: TestParseResourceRKEConfigNodesConf (0.00s)
    --- PASS: TestParseResourceRKEConfigNodesConf/JSON (0.00s)
    --- PASS: TestParseResourceRKEConfigNodesConf/YAML (0.00s)
    --- PASS: TestParseResourceRKEConfigNodesConf/both_JSON_and_YAML (0.00s)
=== RUN   TestParseResourceETCDService
=== RUN   TestParseResourceETCDService/all_fields
--- PASS: TestParseResourceETCDService (0.00s)
    --- PASS: TestParseResourceETCDService/all_fields (0.00s)
=== RUN   TestParseResourceKubeAPIService
=== RUN   TestParseResourceKubeAPIService/all_fields
--- PASS: TestParseResourceKubeAPIService (0.00s)
    --- PASS: TestParseResourceKubeAPIService/all_fields (0.00s)
=== RUN   TestParseResourceKubeControllerService
=== RUN   TestParseResourceKubeControllerService/all_fields
--- PASS: TestParseResourceKubeControllerService (0.00s)
    --- PASS: TestParseResourceKubeControllerService/all_fields (0.00s)
=== RUN   TestParseResourceSchedulerService
=== RUN   TestParseResourceSchedulerService/all_fields
--- PASS: TestParseResourceSchedulerService (0.00s)
    --- PASS: TestParseResourceSchedulerService/all_fields (0.00s)
=== RUN   TestParseResourceKubeletService
=== RUN   TestParseResourceKubeletService/all_fields
--- PASS: TestParseResourceKubeletService (0.00s)
    --- PASS: TestParseResourceKubeletService/all_fields (0.00s)
=== RUN   TestParseResourceKubeproxyService
=== RUN   TestParseResourceKubeproxyService/all_fields
--- PASS: TestParseResourceKubeproxyService (0.00s)
    --- PASS: TestParseResourceKubeproxyService/all_fields (0.00s)
=== RUN   TestParseResourceNetwork
=== RUN   TestParseResourceNetwork/all_fields
--- PASS: TestParseResourceNetwork (0.00s)
    --- PASS: TestParseResourceNetwork/all_fields (0.00s)
=== RUN   TestParseResourceAuthentication
=== RUN   TestParseResourceAuthentication/all_fields
--- PASS: TestParseResourceAuthentication (0.00s)
    --- PASS: TestParseResourceAuthentication/all_fields (0.00s)
=== RUN   TestParseResourceAddons
--- PASS: TestParseResourceAddons (0.00s)
=== RUN   TestParseResourceAddonsInclude
--- PASS: TestParseResourceAddonsInclude (0.00s)
=== RUN   TestParseResourceAddonJobTimeout
--- PASS: TestParseResourceAddonJobTimeout (0.00s)
=== RUN   TestParseResourceSSHKeyPath
--- PASS: TestParseResourceSSHKeyPath (0.00s)
=== RUN   TestParseResourceSSHAgentAuth
--- PASS: TestParseResourceSSHAgentAuth (0.00s)
=== RUN   TestParseResourceBastionHost
=== RUN   TestParseResourceBastionHost/all_fields
--- PASS: TestParseResourceBastionHost (0.00s)
    --- PASS: TestParseResourceBastionHost/all_fields (0.00s)
=== RUN   TestParseResourceMonitoring
=== RUN   TestParseResourceMonitoring/all_fields
--- PASS: TestParseResourceMonitoring (0.00s)
    --- PASS: TestParseResourceMonitoring/all_fields (0.00s)
=== RUN   TestParseResourceAuthorization
=== RUN   TestParseResourceAuthorization/all_fields
--- PASS: TestParseResourceAuthorization (0.00s)
    --- PASS: TestParseResourceAuthorization/all_fields (0.00s)
=== RUN   TestParseResourceIgnoreDockerVersion
--- PASS: TestParseResourceIgnoreDockerVersion (0.00s)
=== RUN   TestParseResourceKubernetesVersion
--- PASS: TestParseResourceKubernetesVersion (0.00s)
=== RUN   TestParseResourcePrivateRegistries
=== RUN   TestParseResourcePrivateRegistries/all_fields
--- PASS: TestParseResourcePrivateRegistries (0.00s)
    --- PASS: TestParseResourcePrivateRegistries/all_fields (0.00s)
=== RUN   TestParseResourceIngress
=== RUN   TestParseResourceIngress/all_fields
--- PASS: TestParseResourceIngress (0.00s)
    --- PASS: TestParseResourceIngress/all_fields (0.00s)
=== RUN   TestParseResourceClusterName
--- PASS: TestParseResourceClusterName (0.00s)
=== RUN   TestParseResourceCloudProvider
=== RUN   TestParseResourceCloudProvider/all_fields
--- PASS: TestParseResourceCloudProvider (0.00s)
    --- PASS: TestParseResourceCloudProvider/all_fields (0.00s)
=== RUN   TestParseResourcePrefixPath
--- PASS: TestParseResourcePrefixPath (0.00s)
=== RUN   TestClusterToState
=== RUN   TestClusterToState/all_fields
--- PASS: TestClusterToState (0.00s)
    --- PASS: TestClusterToState/all_fields (0.00s)
PASS
ok  	github.com/yamamoto-febc/terraform-provider-rke/rke	701.005s
?   	github.com/yamamoto-febc/terraform-provider-rke/tools/plugin-protocol-version	[no test files]
?   	github.com/yamamoto-febc/terraform-provider-rke/tools/terraform-version	[no test files]

[mkozjak]

Seems to be working. It didn't create that 'default' file in the root of my project. Cannot recreate my kube cluster atm and my kube config file wasn't 'refreshed', but it probably shouldn't be, either. Thanks!!