Fix vlan interface handling under FreeNAS 9.
FreeNAS 9 has reached a new level of broken in its handling of network configuration. Essentially each time a vlan interface is added, or IP configuration is added, it wipes all existing vlan configurtion and recreates it from its database. Worse, when IP addresses/aliases are removed, it completely shuts off all network interfaces and re-configures them from scratch. ALL interfaces. All of them. Every last one. Even those that are not in scope for the current modification operation. So, we now do ALL network manipulation, including create/destroy vlan operations, behind FreeNAS's back. As a consequence, FreeNAS's UI will often not show the actual network configuration - it will only list those things that have been set up statically through its interfaces (command line or UI).