* fix the prerm mess. Other packages seem to remove
  /etc/sgml/devilspie.cat in the purge phase, but I don't have a
  purge as I don't have any config files (I guess). Unless you could
  the catalogues as config files... which I'm not sure about. Other
  packages don't list the catalogues as conf files.
* patch the same config file so that it uses the system catalogue
