This is done by creating a new directory, /etc/testbed/rc.d .
This works just like /usr/local/etc/rc.d . Right now, it
only has one script, which does a 'tmcc state REBOOTING' when
called with the 'stop' argment.

While I'm at it, checked in rc.conf - it contains some testbed
specific things now, so it should be in CVS.