+++ This bug was initially created as a clone of Bug #1729866 +++

Description of problem:
The Rally test NeutronNetworks.create_and_list_ports failed:

controller-0/var/log/containers/neutron/server.log.1:2019-07-14 14:38:19.665 31 ERROR neutron.plugins.ml2.managers [req-785fdb51-0cbb-48d2-ad3a-42ead52405c9 4ae467e29c93404bbb765327298cd8f9 560c31a384794fc2b3a1ad8265da87a1 - default default] Mechanism driver 'ovn' failed in create_port_postcommit: RuntimeError: OVSDB Error: {"details":"Transaction causes multiple rows in \"Port_Group\" table to have identical values (neutron_pg_drop) for index on column \"name\". 
and then the rally request fails: 

controller-0/var/log/containers/neutron/server.log.1:2019-07-14 14:38:19.665 31 ERROR neutron.plugins.ml2.managers [req-785fdb51-0cbb-48d2-ad3a-42ead52405c9 4ae467e29c93404bbb765327298cd8f9 560c31a384794fc2b3a1ad8265da87a1 - default default] Mechanism driver 'ovn' failed in create_port_postcommit: RuntimeError: OVSDB Error: {"details":"Transaction causes 

multiple rows in \"Port_Group\" table to have identical values (neutron_pg_drop) for index on column \"name\". 
so it looks, like (from the first message) that two ports tried to have the same value in "name" column which is an index so that's not allowed 
so Rally managed to break the ovndb service with concurrency

Version-Release number of selected component (if applicable):
OSP14- core_puddle: 2019-06-26.1

How reproducible:
100%

Steps to Reproduce:
1. run the job https://rhos-qe-jenkins.rhev-ci-vms.eng.rdu2.redhat.com/view/DFG/view/network/view/networking-ovn/job/DFG-network-networking-ovn-14_director-rhel-virthost-3cont_2comp-ipv4-geneve-dvr-rally/135/
2.
3.

Actual results:


Expected results:


Additional info: