javelin: create and attach volumes

Bring Cinder support in tempest/javelin to test:
- volume creation
- volume attachement to a server

Partial-Bug #1330178
Signed-off-by: Emilien Macchi <emilien.macchi@enovance.com>

Change-Id: Ie0e437312aab3ccb0d8233e4b73f9215f64149ac
Merge "javelin: create and attach volumes"