Cleanup: Remove unnecessary dash escape when building docker container name

We don't need this dash escape since they are not valid name for Container and Pod. Modified test to reflect the changes, and also removed two test cases since they are not allowed in the system anyway. 
I don't get it - I don't see any place that calls this function.  We should never have to unescape an old format - after this PR we will find a container named k8s--<anything> and not be able to parse it, so we will destroy it.  We will also find that the containers we want do not exist and so create them.

What am I missing?  Is there some place that calls this function that I am just not seeing?