Configure CRUSH map appropriately on AIO Ceph

Introduce a parameter which can be used to set up the CRUSH map
optimally in single-node Ceph installations. This allows AIO Ceph
installs to report HEALTH_OK.

Closes-Bug: 1340168
(cherry picked from commit 8f798d16f318b4d6e90905291fb020c9d3eab397)

Conflicts:
	manifests/init.pp
Merge pull request #13 from rickerc/bug/1340168

Configure CRUSH map appropriately on AIO Ceph