Blockstorage compute integration test updates

 * Added integration tests for booting and snapshoting volumes.
 * Improved ComputeIntegration test fixture for better cross-platform
   remote testing.
 * Moved dataset generators to cloducafe
 * Most tests are now data-driven

Change-Id: Iacea94e660ebe1f17582982b64f996b7de0729e9
Merge "Blockstorage compute integration test updates"