The major reason for the addition of this feature is to facilitate
an upgrade to the Pacific Ceph release, which now requires the
require-osd-release flag to be set to the proper release in order
to avoid a cluster warning scenario. Any Ceph command can be run
against the cluster using this feature, however.
Change-Id: I194264c420cfda8453c139ca2b737e56c63ef269
de2227f6e7