Add container hashing to the container name, and restart containers on changes.

Closes https://github.com/GoogleCloudPlatform/kubernetes/issues/677
https://github.com/GoogleCloudPlatform/kubernetes/blob/master/pkg/api/validation.go#L231

shows we test name with IsDNSLabel which matches against the regexp: `a-z0-9]([-a-z0-9]*[a-z0-9])?` so no '.' allowed in names.