Fixed bugs in volumes_api config.py.
Added delete_volume_with_snapshot_confirmed() method to volumes_api behaviors.
Moved BehaviorResponse from blockstorage/volumes_api/behaviors to opencafe/engine/models/behavior_response
I79a40618cc2b2b26eb751bb9e2bf221dc57f1ae7

Change-Id: Iab9bdbf9086c68a57438779b553cfdb9fded0832