New mac-in-use field in ovsdb termination-point augmentation breaks copying node from config to operational

ElanOvsdbNodeLiIstener receives notifications of new nodes. When a node is discovered for which there is no entry in the config datastore we copy it over so that we can than make modifications to it. A new field, mac-in-use, was added and it is operational only so when attempting to write the bridge to config the whole thing fails.