Trying to add inet6 address w/o inet6 support resets interface configuration

[Scott Ellis <scotte%warped.com@localhost>]

I noticed this on the May 5th kernel+userland, and just now got a chance 
to try it on today's kernel+userland.

I always build my systems w/o INET6 (no need for it yet). 
Unfortunately, after boot, lo0 isn't configured.  Turns out running 
"ifconfig lo0 inet6" (as is done twice in rc.d/network) results in a 
SIOCAIFADDR error, that removes the configuration entirely. :-(

For example...

intrepid{~}# ifconfig lo0
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 33648
        inet 127.0.0.1 netmask 0xff000000
intrepid{~}# ifconfig lo0 inet6
lo0: SIOCAIFADDR: Address family not supported by protocol family
intrepid{~}# ifconfig lo0
lo0: flags=8049<UP,LOOPBACK,RUNNING,MULTICAST> mtu 33648
intrepid{~}#

I suspect this is from the "extensible ifconfig" changes.

        ScottE