Remove cinder-volume from required elements, add cinder-volume-nfs instead
Remove cinder-volume and add cinder-volume-nfs in instack-sourcerc too
Cherry-pick the block & object storage t-h-t patch
Merge pull request #31 from tomassedovic/patch-2

Cherry-pick the block & object storage t-h-t patch
Merge pull request #29 from gfidente/master

Remove cinder-volume from image elements, add cinder-volume-nfs instead