osd: lock pg when requeuing requests
osd: lock pg when requeuing requests

The op queue is shut down, so this is mostly safe, unless someone comes
through and does requeue_ops() from a callback or something.

Signed-off-by: Sage Weil <c5b6ff1fd4f0bde10db63d7a3e07166cf6c4229f@dreamhost.com>

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