ceph: close out mds, osd connections before stopping auth

The auth module (part of the mon_client) is needed to free any
ceph_authorizer(s) used by the mds and osd connections.  Flush the msgr
workqueue before stopping monc to ensure that the destroy_authorizer
auth op is available when those connections are closed out.

Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/messenger.h b/fs/ceph/messenger.h
index 00a9430..76fbc95 100644
--- a/fs/ceph/messenger.h
+++ b/fs/ceph/messenger.h
@@ -213,6 +213,7 @@
 
 extern int ceph_msgr_init(void);
 extern void ceph_msgr_exit(void);
+extern void ceph_msgr_flush(void);
 
 extern struct ceph_messenger *ceph_messenger_create(
 	struct ceph_entity_addr *myaddr);