Bicho gets a 502 error getting 500 bugs in XML from a Bugzilla instance

[canasdiaz]

The server couldn't fulfill the request.
Error code: 502
Traceback (most recent call last):
  File "/usr/local/bin/bicho", line 25, in <module>
    retval = Bicho.main.main()
  File "/usr/local/lib/python2.7/dist-packages/Bicho/main.py", line 56, in main
    backend.run()
  File "/usr/local/lib/python2.7/dist-packages/Bicho/backends/bg.py", line 952, in run
    self._process_issues()
  File "/usr/local/lib/python2.7/dist-packages/Bicho/backends/bg.py", line 1047, in _process_issues
    self._retrieve_issues(ids, url, self.tracker.id)
  File "/usr/local/lib/python2.7/dist-packages/Bicho/backends/bg.py", line 1101, in _retrieve_issues
    self._safe_xml_parse(url, handler);
  File "/usr/local/lib/python2.7/dist-packages/Bicho/backends/bg.py", line 1247, in _safe_xml_parse
    f = self._urlopen_auth(bugs_url)
  File "/usr/local/lib/python2.7/dist-packages/Bicho/backends/bg.py", line 1178, in _urlopen_auth
    return aux
UnboundLocalError: local variable 'aux' referenced before assignment