Fix Nova Cinder Interaction

Currently the Nova Cinder interaction seems to be broken leading to Cinder volumes being left in "ing" (attaching, detaching) state. When a volume goes in this "ing" state the volume is not re-usable since in-order to re-attach a volume, the volume needs to be in "available" state (and for detaching it needs to be "in-use"). Nova makes some really bad assumptions about the calls into cinder. It sometimes doesn't even check to see if an exception happens or not. Cinder needs to check volumes in an 'ing' state, and if the volume is in an active 'ing' state, then it reports volume busy exception, which nova isn't looking for. Etherpad has more details [1]

In short,

There are 8 different ways Nova interacts with Cinder. The effort aims at fixing those and help to improve Nova Cinder interaction and not let Nova take decisions for Cinder depending on the volume state Cinder volumes are in.

[1] https://etherpad.openstack.org/p/CinderNovaAPI