message: change maintainer
diff: <url type="website">http://ros.org/wiki/schunk_sdh</url>
  <!-- <url type="bugtracker"></url> -->
  - <maintainer email="mdl@ipa.fhg.de">Mathias Luedtke</maintainer>
  + <maintainer email="fmw@ipa.fhg.de">Florian Weisshardt</maintainer>
  <author email="mdl@ipa.fhg.de">Mathias Luedtke</author>
  <author email="fmw@ipa.fhg.de">Florian Weisshardt</author>
  