By the time list_net_interfaces() is called in /etc/rc.d/netif, clone_up()

By the time list_net_interfaces() is called in /etc/rc.d/netif,  clone_up()
has already created each of $cloned_interface and they will show up in
the ifconfig -l.  There is no need to add $cloned_interfaces to the list
(it will result in the cloned interfaces being configured twice).

Submitted-by: Chris Csanady <cc@137.org>