libceph: kill bad_proto ceph connection op

(cherry picked from commit 6384bb8b)

No code sets a bad_proto method in its ceph connection operations
vector, so just get rid of it.
Signed-off-by: Alex Elder <elder@inktank.com>
Reviewed-by: Yehuda Sadeh <yehuda@inktank.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

include/linux/ceph/messenger.h

@@ -31,9 +31,6 @@ struct ceph_connection_operations {
 	int (*verify_authorizer_reply) (struct ceph_connection *con, int len);
 	int (*invalidate_authorizer)(struct ceph_connection *con);
 
-	/* protocol version mismatch */
-	void (*bad_proto) (struct ceph_connection *con);
-
 	/* there was some error on the socket (disconnect, whatever) */
 	void (*fault) (struct ceph_connection *con);
 

net/ceph/messenger.c

@@ -1360,11 +1360,6 @@ static void fail_protocol(struct ceph_connection *con)
 {
 	reset_connection(con);
 	set_bit(CLOSED, &con->state);  /* in case there's queued work */
-
-	mutex_unlock(&con->mutex);
-	if (con->ops->bad_proto)
-		con->ops->bad_proto(con);
-	mutex_lock(&con->mutex);
 }
 
 static int process_connect(struct ceph_connection *con)