setup.py: reload __version__.py after writing it. write_version loads __version__.py before writing it (see 7eb694a1c1af), so we have to explicitly reload it to use the correct version. Problem diagnosed by Christian Ebert.

Content-type: text/xml; charset={encoding}

<?xml version="1.0" encoding="{encoding}"?>
<rss version="2.0">
  <channel>
    <link>{urlbase}{url}</link>
    <language>en-us</language>