Adapt for cinder multi-backend support
Also adapt nova recipe for cinder multi-backend
Use ceph_client chef resource to create the clients for cinder
Use ceph_client chef resource to create the client for nova
Use ceph_client chef resource to create the client for glance
Merge pull request #73 from vuntz/cinder-multi-backend

Adapt for cinder multi-backend support + move to ceph_client chef resource