Comment 3 for bug 1856152

In nova.conf, The CONF.neutron.ovs_bridge configuration item is not configured.
But in neutron.conf, The cfg.CONF.OVS.integration_bridge configuration item is configured to `br-int-ovs`
Error handling will occur here:
https://github.com/openstack/nova/blob/b6e353a2c84d87bbb1353ff6602f9f13dc62a2fd/nova/network/neutronv2/api.py#L2921

So,i think,we shuold put "portbindings.VIF_DETAILS_BRIDGE_NAME: cfg.CONF.OVS.integration_bridge" to vif_details
https://github.com/openstack/neutron/blob/e04e1d80e465a04b831047ac0ffb566c80cdd029/neutron/plugins/ml2/drivers/openvswitch/mech_driver/mech_openvswitch.py#L64