FEATURE: Remove docker daemon from the buildroot iso

[frezbo]

Minikube version: minikube version: v0.28.2

• OS :

Linux frezbo 4.17.12-200.fc28.x86_64 #1 SMP Fri Aug 3 15:01:13 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux

Bootstrapped a cluster using this command:

minikube -v 5 start --network-plugin=cni --container-runtime=cri-o --bootstrapper=kubeadm --vm-driver=kvm2

After minikube ssh , I see docker daemon running even though CRIO-O is used as runtime

[afbjorklund]

It will also load the cached images using docker load, see #2757

Then again, I think the ISO runs rkt too - just to be on the safe side

[afbjorklund]

@tstromberg : this feature is also a "runtime/crio" label, same as with #2757
(the current system is still hardcoded to run docker, in a couple of places)

[afbjorklund]

As long as we are using docker machine, I guess the daemon will be around...
But one could at least stop it from running, when configuring another runtime ?

sudo systemctl stop docker
sudo systemctl stop crio
sudo systemctl stop rkt-api
sudo systemctl stop rkt-metadata

Could do this in a similar place to where we are configuring the /etc/crictl.yaml*
Should probably be done before calling kubeadm bootstrapper, to install k8s ?

* in #3194