Prevent tenant viewing volumes owed by another

Bug introduced by 0505bb268942534ad5d6ecd5e34a4d9b0e7f5c04 allows any
tenant to get the details of a volume belonging to any other tenant
if the UUID is known.

This commit allows only the tenant or an admin to get a volume.

Change-Id: I0268d374f7529d89068dcbf3c1cb9ab3d60d4115
Closes-Bug: #1356368
Merge "Prevent tenant viewing volumes owed by another"