Retain some support for Python2.

Allow for running under Python 2.6 or 2.7. The invocation needs to be
`python update_repos`.

update_repos

 #!/usr/bin/env python3
 # encoding: utf-8
 
+from __future__ import (print_function, unicode_literals)
 import base64
 import sys
 import os
 import argparse
 from collections import namedtuple
 from subprocess import Popen, PIPE
+import json
 
-from urllib.parse import urlencode
+try:
+    from urllib.parse import urlencode, urlparse
     from urllib.request import Request, urlopen
-import json
-from urllib.parse import urlparse
+except ImportError:
+    from urllib import urlencode
+    from urllib2 import Request, urlopen
+    from urlparse import urlparse
 
 WHITELIST=[]
 BLACKLIST=[]