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
Set "cephx require signatures" to true

This is false by default, but only for backwards compatibility with old
releases. Let's be secure by default!
Avoid some unneeded empty lines in ceph.conf
Merge pull request #78 from vuntz/require-signatures

Set "cephx require signatures" to true
Merge pull request #73 from vuntz/cinder-multi-backend

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