Comment 1 for bug 1604862

Attempts of MySQL Galera to get access to locked records manifests itself as MySQL deadlock error.
This problem described in http://lists.openstack.org/pipermail/openstack-dev/2015-February/056007.html and http://www.joinfu.com/2015/01/understanding-reservations-concurrency-locking-in-nova/

Adding retries of revoke should solve this problem.