osd: take osd_lock in generate_backlog before peer()
osd: take osd_lock in generate_backlog before peer()

Peer() uses the osd.timer to schedule the replay interval, which
needs osd_lock.

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