Updates test_007_me_can_detach_volume so that it waits for
the volume status to become active for up to 10 seconds
after initiating the command to detach the volume.
Previously it just waited for 5 seconds without checking the
status which can be problematic in that it causes the
subsequent test to delete the volume to fail intermittently
(because only active or error volumes can be deleted).
I noticed this in SmokeStack because 2 days ago this commit landed:
b46f224f7555e3065b0daacd101b65d86117f0c1
and it is now causing a fair amount of intermittent volume
tests to fail for Nova and Cinder. Apparently now that we
have ordered the commands to remove an iscsi target properly
it takes a bit longer...
Change-Id: Ibfd25af93f9cb063a76a04138b8d23d28a01b89a