After stopping any runtimes that aren't being used, if we're using
containerd then we need to restart it. This is because it competes with
cri-o to listen on port 10010, causing a necesary plugin to not be
installed. After stopping cri-o, we need to restart containerd so that
the plugin is installed.

I also added some preflight checks when using alternative runtimes.
kubeadm checks to make sure the Docker service is running, so I disabled
that. It also checks if a few ports are available; these are ports that
containerd uses, so I also added them to the ignore list.

This should finish the work started in kubernetes#3211, which stopped alternative
runtimes but didn't restart containerd. I was able to run "minikube
start" with containerd locally with this change.