Fix for default PG settings

The default PG settings chosen by the barclamp-ceph are really poor for bigger
deployments, since it scales the PGs by number of osd nodes. If the osd node
has many disks or very few disks, these are really off.

https://bugzilla.novell.com/show_bug.cgi?id=896409
can you raise that to 20 to give some free numbers for migrations on older code branches?