Fix responses to volume attach commands.

Fixes bug 1064455

Change-Id: I5b155a4fe83220b1cd06a66b41264eaa5e37f508
This change will fix this bug https://bugs.launchpad.net/openstack-api-site/+bug/1092662

Change-Id: I2bfc7e8284815691dc9f76e74e45b105ac0e489c
Merge "Fix responses to volume attach commands."