BridgeDB's DKIM validator seems to be broken

I didn't even know we were using this Python package -- it wasn't mentioned in any of the docs, nor the requirements.txt file, and not to mention it appears to be installed via the system package manager.

This seems to be the package, and these are the errors:

Traceback (most recent call last):
  File "/usr/bin/dkimverify", line 40, in <module>
    res = dkim.verify(message)
  File "/usr/lib/python2.7/dist-packages/dkim/__init__.py", line 603, in verify
    return d.verify(dnsfunc=dnsfunc)
  File "/usr/lib/python2.7/dist-packages/dkim/__init__.py", line 505, in verify
    validate_signature_fields(sig)
  File "/usr/lib/python2.7/dist-packages/dkim/__init__.py", line 180, in validate_signature_fields
    if int(sig[b'x']) < int(sig[b't']):
KeyError: 't'

and

Traceback (most recent call last):
  File "/usr/bin/dkimverify", line 40, in <module>
    res = dkim.verify(message)
  File "/usr/lib/python2.7/dist-packages/dkim/__init__.py", line 603, in verify
    return d.verify(dnsfunc=dnsfunc)
  File "/usr/lib/python2.7/dist-packages/dkim/__init__.py", line 538, in verify
    s = dnsfunc(name)
  File "/usr/lib/python2.7/dist-packages/dkim/dnsplug.py", line 82, in get_txt
    txt = _get_txt(unicode_name)
  File "/usr/lib/python2.7/dist-packages/dkim/dnsplug.py", line 31, in get_txt_dnspython
    a = dns.resolver.query(name, dns.rdatatype.TXT,raise_on_no_answer=False)
  File "/usr/lib/python2.7/dist-packages/dns/resolver.py", line 920, in query
    raise_on_no_answer, source_port)
  File "/usr/lib/python2.7/dist-packages/dns/resolver.py", line 847, in query
    timeout = self._compute_timeout(start)
  File "/usr/lib/python2.7/dist-packages/dns/resolver.py", line 692, in _compute_timeout
    raise Timeout
dns.exception.Timeout

procmail: [11285] Thu Jun 20 13:07:45 2013
procmail: No match on "^To: yangcong@bridges.torproject.org"
procmail: Executing "formail,-I,X-DKIM-Authentication-Results: dunno"
procmail: Match on "^DKIM-Signature:"
procmail: Executing "dkimverify"
procmail: Non-zero exitcode (1) from "dkimverify"
procmail: No match on "dkimverify"
procmail: Executing "esmtp,-C,/srv/bridges.torproject.org/etc/estmprc-bridgedb-deliver,bridges@bridgedb"
procmail: Assigning "LASTFOLDER=esmtp -C /srv/bridges.torproject.org/etc/estmprc-bridgedb-deliver bridges@bridgedb"
procmail: Notified comsat: "bridgedb@:/home/bridgedb/esmtp -C /srv/bridges.torproject.org/etc/estmprc-bridgedb-deliver bridges@bridgedb"
From aagbsn@gmail.com  Thu Jun 20 13:07:45 2013
 Subject: get bridges
  Folder: esmtp -C /srv/bridges.torproject.org/etc/estmprc-bridgedb-de     3524
procmail: [11291] Thu Jun 20 13:07:47 2013
procmail: No match on "^To: yangcong@bridges.torproject.org"
procmail: Executing "formail,-I,X-DKIM-Authentication-Results: dunno"
procmail: Match on "^DKIM-Signature:"
procmail: Executing "dkimverify"
procmail: Non-zero exitcode (1) from "dkimverify"
procmail: No match on "dkimverify"
procmail: Executing "esmtp,-C,/srv/bridges.torproject.org/etc/estmprc-bridgedb-deliver,bridges@bridgedb"
procmail: Assigning "LASTFOLDER=esmtp -C /srv/bridges.torproject.org/etc/estmprc-bridgedb-deliver bridges@bridgedb"
procmail: Notified comsat: "bridgedb@:/home/bridgedb/esmtp -C /srv/bridges.torproject.org/etc/estmprc-bridgedb-deliver bridges@bridgedb"
From aagbsn@gmail.com  Thu Jun 20 13:07:47 2013
 Subject: get bridges
  Folder: esmtp -C /srv/bridges.torproject.org/etc/estmprc-bridgedb-de     4344

Those are old logs, but the errors are still happening.