Knowing which cloner an interface came from isn't always easy,
especially if a driver has multiple cloner candidates and we need to
find the right cloner for the correct driver in the home vnet. We have
the information needed, but it's a lot cleaner to just let the clone
infrastructure handle it.
This will be used in a future patch to allow tun(4)/tap(4) devices to
be configured as transient and automatically destroyed on last close of
the device.