In a diskless setup, rc.d/initdiskless may overwrite parts of /etc on

In a diskless setup, rc.d/initdiskless may overwrite parts of /etc on
a per-machine or per-cluster (with different ways of expressing what's
part of a cluster) basis.  In order for this to be effective, rc.conf
has to be reread after initdiskless is finished.  Implement this by
adding a hook to etc/rc which rereads rc.conf by request.  This can
also be implemented by renaming initdiskless to initdiskless.sh and
sourcing rc.conf there manually, but it was decided that, that would
be uglier than a hook in etc/rc.

Developed in concert with:	gordon