Fix NotImplementedError for TPE and Random suggestion.

[c-bata]

What this PR does / why we need it:

I deployed katib (rev ab3dab0) to my kubernetes cluster, then applied this experiment which specifies random as an algorithmName attribute.

$ kubectl logs cmaes-example-random-7dd54668f8-ffgvs -n kubeflow
ERROR:grpc._server:Exception calling application: Method not implemented!
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/grpc/_server.py", line 434, in _call_behavior
    response_or_iterator = behavior(argument, context)
  File "/usr/src/app/github.com/kubeflow/katib/pkg/apis/manager/v1alpha3/python/api_pb2_grpc.py", line 135, in ValidateAlgorithmSettings
    raise NotImplementedError('Method not implemented!')
NotImplementedError: Method not implemented!

I checked the implementation of hyperopt suggestion service, but it doesn't implement ValidateAlgorithmSetttings. So this method is called.

I tested this patch on my Kubernetes cluster, then this problem is resolved. But I don't know what should I validate in this method, so I just added an empty implementation of ValidateAlgorithmSettings for now.

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
None

Special notes for your reviewer:

1. This problem also happens when using tpe algorithm.
2. Please tell me if I should put a todo comment.

Release note:

None

I guess this bug was recently added.

[kubeflow-bot]

This change is 

[k8s-ci-robot]

Hi @c-bata. Thanks for your PR.

I'm waiting for a kubeflow member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

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[c-bata]

I also checked examples/v1alpha3/tpe-example.yaml.

Before

$ kubectl apply -f ./examples/v1alpha3/tpe-example.yaml
$ kubectl -n kubeflow logs -f tpe-example-tpe-5898d78478-k6kkk
ERROR:grpc._server:Exception calling application: Method not implemented!
Traceback (most recent call last):
  File "/usr/local/lib/python3.6/site-packages/grpc/_server.py", line 434, in _call_behavior
    response_or_iterator = behavior(argument, context)
  File "/usr/src/app/github.com/kubeflow/katib/pkg/apis/manager/v1alpha3/python/api_pb2_grpc.py", line 135, in ValidateAlgorithmSettings
    raise NotImplementedError('Method not implemented!')
NotImplementedError: Method not implemented!
INFO:hyperopt.tpe:build_posterior_wrapper took 0.002016 seconds
INFO:hyperopt.tpe:TPE using 0 trials

After

$ kubectl apply -f ./examples/v1alpha3/tpe-example.yaml
$ kubectl -n kubeflow logs tpe-example-tpe-94b986568-6wphh
INFO:hyperopt.tpe:build_posterior_wrapper took 0.001426 seconds
INFO:hyperopt.tpe:TPE using 0 trials

[gaocegege]

LGTM.

FYI, This year we will add validation for all algortihms.

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: gaocegege

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