Add a init method to CNDB.OMP.Net_Interface_in_IP_Network that calls a new method of IP_Network, e.g., un_de_allocate, to deal with the case that the garbage collector has run between the de-allocation (i.e., destory of Net_Interface_in_IP_Network) and the undo operation:
- reset cool_down, if any
- set owner correctly
- ...