A little script that renews our plab slices that were instantiated via

the planetlab web interface (instead of over xmlrpc).  If the slice is
due to expire within a week, I renew it for 4 weeks.  The script looks
at /usr/testbed/etc/plab/metaslices to get the slices to check and
renew.  I've put it in cron on boss so it runs nightly.