Give each cli its own test.

This will give a nicer failure message, and results in 3
slowish tests instead of 1 really slow one.

Change-Id: I5c3fbd2507068908c165e163b8f458bf8cb00bc1
Support SnapshotId in volume creation.

This uses cinder backups as snapshot, to be symmetrical to the deletion
policy.

Change-Id: Ie8f1ff095df7bdad8500c6298d1b7d9fd233693f
Implements: blueprint bp/volume-snapshots
Merge "Support SnapshotId in volume creation."
Merge "Give each cli its own test."