panic after "ifconfig gif0 destroy"

[J.R. Oldroyd]

The command:
	# ifconfig gif0 destroy
	panic: page fault

isn't really ideal behavior.  Previously it simply removed the gif0
tunnel interface and the system continued.

Kernel is FreeBSD 6.0 -current cvsup'd just before: Tue Sep 28
15:27:07 EDT 2004.

Things are OK on my previous kernel which was cvsup'd on 9/20.

That command is invoked in the freenet6 config script
/usr/local/bin/tspc-freebsd44.sh and is used whenever a freenet6
IPv6 tunnel is being re-configured.

	-jr