set osd_pool_default_pgp_num from fuel_settings

Puppet doesn't reuse value of the osd_pool_default_pg_num parameter of
the ceph class, so osd_pool_default_pgp_num has to be populated
separately from the same storage setting value in the fuel_settings.

Change-Id: Ia0b4481161b31581292d7a4a2ee6c19e78e9dedd
Closes-Bug: #1359321
Merge "set osd_pool_default_pgp_num from fuel_settings"