libceph: fix NULL dereference in reset_connection()

We dereference "con->in_msg" on the line after it was set to NULL.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Alex Elder <elder@inktank.com>

net/ceph/messenger.c

@@ -440,7 +440,7 @@ static void reset_connection(struct ceph_connection *con)
 		con->in_msg->con = NULL;
 		ceph_msg_put(con->in_msg);
 		con->in_msg = NULL;
-		ceph_con_put(con->in_msg->con);
+		ceph_con_put(con);
 	}
 
 	con->connect_seq = 0;