Getting started guide uses deprecated --api-servers option

[Zokormazo]

If you strictly continue the getting started guide kubelet on nodes can't start since it's using deprecated --api-servers option instead of using a kubeconfig

[sylvaingirardbe]

Same problem here. Not just api-servers, also allow-privileged.

Since I'm trying to get an Atomic cluster up and running, I'm willing to create a PR to updated the docs.