DB Deadlock error on VLAN creations

Issue

• In a multi-controller environment, when starting the neutron-server, some of the controllers occasionally crash with below DBDeadlock exceptions:

2016-08-27 00:32:11.937 193309 CRITICAL neutron [-] DBDeadlock: (_mysql_exceptions.OperationalError) (1213, 'Deadlock found when trying to get lock; try restarting transaction') [SQL: u'INSERT INTO ml2_vlan_allocations (physical_network, vlan_id, allocated) VALUES (%s, %s, %s)'] [parameters: (('bond0', 1, 0), ('bond0', 2, 0), ('bond0', 3, 0), ('bond0', 4, 0), ('bond0', 5, 0), ('bond0', 6, 0), ('bond0', 7, 0), ('bond0', 8, 0) ... displaying 10 of 4095 total bound parameter sets ... ('bond0', 4094, 0), ('bond0', 4095, 0))]