when running natd(8) out of the rc-files. It is perfectly valid for
the interface or alias address to be set in a natd(8) configuration
file, not on the command line. Also, loosen up the restrictions on
identifying an IP address argument in 'natd_interface.'
Fix the documentation, rc.conf(5), to reflect this change.
Take the bogus default for 'natd_interface' out of /etc/defaults/rc.conf.
MFC after: 3 days