Remove CinderVolume id attribute

Using the id attribute can result in problems when validating a
template, as the resource_id is empty at that point, so we remove it to
prevent issues, as people ought to use Ref anyway.

Closes-Bug: #1230140
Change-Id: I16778d8036e7e2ccacf93caa4581ae0b0368b7c2
Merge "Remove CinderVolume id attribute"