ctdb-recoverd: Handle cancellation when releasing recovery lock
If the recovery lock is in the process of being taken then free the
cluster mutex handle but leave the recovery lock handle in place.
This allows ctdb_recovery_lock() to fail.
Note that this isn't yet live because rec->recovery_lock_handle is
still only set at the completion of the attempt to take the lock.
BUG: https://bugzilla.samba.org/show_bug.cgi?id=13617
Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>