[ID-433] Dockerize

1) Fix a weird issue where we didn't use :zone to delete VMS... which, of course, meant that we couldn't delete VMs. (This was a new feature as of last week, but we should have caught that in the previous PR.)

2) Dockerized kitchen-cleaner
It's somewhat arbitrary, but yes. In our present configuration for `intox-jenkins::kitchen-cleaner`, this image is called with the Google client key bind-mounted to this directory. So, it needs to exist.

I could, conceivably, change that to a directory we've got a good bet exists, but I'd think that to be an appropriate place for the file on a bare metal system, and it works presently.

Thoughts?