Remove osd_pool_default_min_size to allow Ceph cluster to do the right thing by default

Remove osd_pool_default_min_size to allow Ceph cluster to do the right thing by default

The default value is 0 which has the minimum number be caluclated based on the replica count
from osd_pool_defaut_size. The default replica count is 3 and the calculated min_size is 2.
If the replica count is 1 then the min_size is 1. ie: min_size = replica - (replica/2)
Add CephPoolDefaultSize parameter to ceph-mon.yaml. This parameter defaults to 3 but can
be overriden. See puppet-ceph-devel.yaml for an example

Change-Id: Ie9bdd9b16bcb9f11107ece614b010e87d3ae98a9