There are a few other places where it may be appropriate to do the bridge removal during error paths; this same search may show you some of them, and some others may show up when you search for where virNetDevTapCreateInBridgePort.
Wouldn't it be simpler to do port removal just inside the networkReleaseActualDevice() function if this is interface that was attached to an OVS bridge? Would this make any problems to the overall design? The code seems to work...