Update openstack.common.

The following things got updated mainly:
- notifier: removed deprecated grizzly features.
- rpc: enabled message envelope.

Change-Id: I830f15363d21bcee6e93771f9457408d2adff2d8
update devstack instructions for cinder

update devstack documentation to include instructions on how to
enable cinder notifications

fix docstring in volume notifications to say volume instead of compute

Change-Id: I9491b4384b212f973211da7e7f716cd7d11d8052
Imported Translations from Transifex

Change-Id: I0901dcab73ef5be665b5e9eddb5e142e434d6d74
Merge "Update openstack.common."
Merge "update devstack instructions for cinder"
Merge "Imported Translations from Transifex"