ovsdb: cleanup ovs initial interfaces during factory start
When NetworkManager shuts down, it is not done properly. We cannot ensure that all pending async operations are cancelled and therefore there are possible device leaks. This means that not all the devices will be disposed and finalized because a different component is handling a reference to it.
Since the l3cfg refactor, this is affecting to ovs ports. When shutting down sometimes there are ovs-interface or ovs-port devices that are not being cleared correctly. When starting NetworkManager back, these devices are not going to be created again because they already exist and the existing compatible connections will be instruct to use the device. But currently, ovsdb is only cleaning up OVS initial interfaces when a bridge is created or modified. This is wrong, because it will left an inconsistent state in NetworkManager and the ovs-port/ovs-interface connection won't be activated.
ovsdb must clean the initial interfaces during the NMManager start up to make sure the virtual devices required are being created and tracked by NetworkManager.