ovs: avoid ovs error when same MAC is set on a local interface and bridge
If the same MAC address is set on both the bridge connection and the interface connection, and the interface is local, NM currently sets the hwaddr record in both Bridge and Interface ovsdb tables. As a result, ovs complains with error:
bridge|ERR|interface br0: ignoring mac in Interface record (use Bridge record to set local port's mac)To avoid this error that looks confusing to users, only set the MAC in the Bridge record, taking it from the ovs-interface. Note that if two different MAC addresses are set, NM emits a warning.