Lock attach_volume

There are some issues with instance and volume cleanup when the volume
is not in a fully attached state so it will be safer to not attempt a
terminate_instance while there are attachments in progress.

Change-Id: I4347794e51004a881bf4ef5ee30f65ac28773e51
Closes-Bug: #1355348
fix up assertEqual(None...) check to catch more cases

To finally close out bug #1280522 it turned out that our hacking check
to eliminate assertEqual(None, ...) was pretty sub optimal. The
perfect fix would actually use the tokenizer, however this is a better
regex which catches a few more missing bits in our codebase. It's
probably close enough for most of what we need.

Fix the relevant tests that would fail the updating hacking check.

Change-Id: Ic8cb1192e001409d827c8da55fe536681895944b
Closes-Bug: #1280522
Merge "fix up assertEqual(None...) check to catch more cases"
Merge "Lock attach_volume"