After BZ1591206 and BZ1592333, ovs bridges mac-table-size has to be
configured to 50000, affecting both ml2/ovs and ml2/ovn deployments
Due to BZ1695122, this verification will only be performed before any
overcloud node is rebooted - this will be changed when BZ1695122 is
resolved
Change-Id: I8bb40e04ba044ed04ffeb8fdffd20d595b0d9168