inconvenient time during boot.
this may be fixed a different way in the long term... (not that the old
rc.shutdown supported stopping the network, or could i really see a
practical use for allowing it at this stage, but in the future someone
might want the functionality i've just disabled).
This replaces the previous /etc/rc.d/sysctl. Also, the variables are now
set earlier, between ipf/ipnat and the network coming up.
The rc.conf defcorename and securelevel variables are no more. You can
set them directly in sysctl.conf now.
thorpej