osd: drop messages from before we moved back to boot state
osd: drop messages from before we moved back to boot state

We want to make sure we ignore any messages sent to us before we moved
back to the boot state (after being wrongly marked down).  This is only
a problem currently while we are in the BOOT state and waiting to be
re-added to the map, because we may then call _share_map_incoming and
send something on the new rebound messenger to an old peer.  Also assert
that we are !booting there to be sure.

Signed-off-by: Sage Weil <6dd34506bbd5e58221bbb3e4732d97c91f02277b@newdream.net>

ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph,ajnelson/ceph