ceph: close old con before reopening on mds reconnect

When we detect a mds session reset, close the old ceph_connection before
reopening it.  This ensures we clean up the old socket properly and keep
the ceph_connection state correct.

Signed-off-by: Sage Weil <sage@inktank.com>
Reviewed-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>

fs/ceph/mds_client.c

@@ -2518,6 +2518,7 @@ static void send_mds_reconnect(struct ceph_mds_client *mdsc,
 	session->s_state = CEPH_MDS_SESSION_RECONNECTING;
 	session->s_seq = 0;
 
+	ceph_con_close(&session->s_con);
 	ceph_con_open(&session->s_con,
 		      CEPH_ENTITY_TYPE_MDS, mds,
 		      ceph_mdsmap_get_addr(mdsc->mdsmap, mds));