vlans and cloning

[Sam Leffler]

I committed the revised netif cloning api so you can now specify
parameters when cloning.  I also modified the vlan code to use this
mechanism so doing something like:

ifconfig vlan create vlan 1 vlandev em0

causes a single request to clone a vlan together with the tag+parent
device parameters (i.e. and no subsequent SIOCSETVLAN request).

Given the above do we still need to support setting vlan tag+device
separately or can we just require everything be specified when doing the
clone operation?  This would change the user api but otherwise I can see
no reason for continuing to support the old mechanism where you do:

ifconfig vlan create
ifconfig vlan0 vlan 1 vlandev em0

Anyone _against_ nuking the above?

	Sam