client: remove default value for pg_num in pools creation
client: remove default value for pg_num in pools creation

trying to set the default value for pg_num to
`hostvars[groups[mon_group_name][0]]['osd_pool_default_pg_num'])` will
break in case of external client nodes deployment.
the `pg_num` attribute should be mandatory and be tested in future
`ceph-validate` role.

Signed-off-by: Guillaume Abrioux <30a9df5a0293a6108675377fa1673f7aa713f915@redhat.com>

ceph/ceph-ansible,fgal/ceph-ansible,fgal/ceph-ansible,font/ceph-ansible,ceph/ceph-ansible,font/ceph-ansible