The configuration that we are using by default that
sets pg_num and pgp_num values in bootstrap_ceph
breaks devstack-plugin-ceph when using the latest Ceph version (quincy).
This patch sets removes the config for pg_num and pgp_num,
so we delegate to Ceph the pools autoscaling.
Closes-Bug: #1983107
Change-Id: Iecd949ef2258ae8a6ded596219bb993aeff20de5
22d94f462e