change the volume_support default to False

With volume_support enabled, trove will require that new instances use
swift. It works fine without swift though and I suppose we want to avoid
an unneeded dependency on swift.
No. I did not have a swift proposal when I created this proposal. This looks like a barclamp-crowbar bug.

I don't see how that second test is better than the one I have proposed here. Or did you mean to add it in a different place?