Dupplicate entries in rest/m/allmaintainers.xml

With latest 1.1.5-dev source (today repo source files), when I build my channel where I provide four packages, I got this file contents:

    <?xml version="1.0" encoding="UTF-8" ?>
    <m xmlns="http://pear.php.net/dtd/rest.allmaintainers" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xlink="http://www.w3.org/1999/xlink" xsi:schemaLocation="http://pear.php.net/dtd/rest.allmaintainers http://pear.php.net/dtd/rest.allmaintainers.xsd">
      <h xlink:href="/rest/m/farell">farell</h>
      <h xlink:href="/rest/m/farell">farell</h>
      <h xlink:href="/rest/m/remicollet">remicollet</h>
      <h xlink:href="/rest/m/farell">farell</h>
      <h xlink:href="/rest/m/farell">farell</h>

    </m>    

This PR fix the dupplicated entries.

Regards,