br-ex dissappears whenever network service is restarted

Issue

• Red Hat Enterprise Linux OpenStack Platform 5 on RHEL7 was recently installed with Neutron Networking, All Bridges and interfaces connected and running. However, whenever I restart the network service (I have NetworkManager disable), the br-ex bridge is removed along with the interface. I have reconfigured it several times in different ways, but end up with the same result.