Add a virtualenv-based python bootstrapping service to infra.

infra/services/lkgr_finder/__main__.py

 #!/usr/bin/env python
 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Fetch the latest results for a pre-selected set of builders we care about.
 If we find a 'good' revision -- based on criteria explained below -- we
 mark the revision as LKGR, and POST it to the LKGR server:
 
 http://chromium-status.appspot.com/lkgr
@@ skipping 48 matching lines @@
 import re
 import smtplib
 import socket
 import subprocess
 import sys
 import textwrap
 import threading
 import urllib
 import xml.etree.ElementTree as xml
 
+import requests
+
 from infra.libs import git
 
-from infra.ext import requests
-
 
 LOGGER = logging.getLogger(__name__)
 RUN_LOG = []
 
 
 GIT_HASH_RE = re.compile('^[a-fA-F0-9]{40}$')
 
 
 ##################################################
 # Helper classes
@@ skipping 856 matching lines @@
                    '%s%s LKGR (%s) exceeds lag threshold' %
                    (subject_base, args.project, lkgr),
                    '\n'.join(RUN_LOG), args.dry_run)
         return 1
 
   return 0
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))