osd: record require_osd_release in objectstore meta

osd: record require_osd_release in objectstore meta

Record the require_osd_release value from the OSDMap in the 'meta' portion
of the osd's metadata that can be accessed without actually mounting the
OSD.  This will be useful as a safety gate to prevent you from mounting
an osd thet is too new that may make incompatible changes to the store.

Signed-off-by: Sage Weil <sage@redhat.com>
(cherry picked from commit 482cdca55351ca85290f1b2adb3c0cdf78af411d)

Conflicts:
	src/osd/OSD.cc
	src/osd/OSD.h
- ignore differences in surrounding context, as they do not seem relevant to
  the fix