horrible prerm bug -- fixes uploaded

[Alan Sundell]

Hahaha whoops! The prerm/preun scripts for Debian/RedHat were really
unsafe ("rm -rf $CACHE/*") if you had a slack.conf with an empty or
unset CACHE! I can't believe I wrote that and didn't catch it... the
bug should be obvious upon inspection.

Thank goodness I haven't heard of any instances of severe data loss.
Thanks to Serge de Souza for pointing out this bug.

I don't think this warrants a new release of slack itself (since the
software version does not change), but you can grab the new
distribution ancillary files directly:

New debian directory:
http://slack.googlecode.com/files/slack-0.15.2-1-debian.tar.gz
New .spec file:
http://slack.googlecode.com/svn-history/r194/slack/trunk/slack.spec

This is what I get for maintaining copies of these distro files
myself. These changes will of course get picked up in future release
tarballs, and Andrew Pollock is making sure Debian gets updated.

In the meantime, make sure you don't have an empty slack.conf when
removing the package! :)

--Alan