Description of problem: A test-only bug for QE to verify operation of OpenStack/Neutron with OVS 2.4.0.
Have tested on AIO with openvswitch-2.4.0-1.el7.x86_64. Tempest with neutron scenarios - all passed: tempest.scenario.test_minimum_basic tempest.scenario.test_network_advanced_server_ops tempest.scenario.test_network_basic_ops tempest.scenario.test_network_v6 tempest.scenario.test_security_groups_basic_ops tempest.scenario.test_server_basic_ops tempest.scenario.test_server_multinode tempest.scenario.test_shelve_instance tempest.scenario.test_snapshot_pattern tempest.scenario.test_stamp_pattern