Create a spec that helps deal with some of the state issues

Propose a spec that will help deal with the issue of
concurrent resource mutation, starting with integrating this
work in the create_volume code (and eventually as it is proven
to work) expanding this solution to other workflows in cinder.

Change-Id: I97fe26d68fce5ce891c9e560852a0f94753b87b6
Merge "Create a spec that helps deal with some of the state issues"