Switch CheckOwners to use input_api.rietveld.

rietveld.py

 # Copyright (c) 2011 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.
 """Defines class Rietveld to easily access a rietveld instance.
 
 Security implications:
 
 The following hypothesis are made:
 - Rietveld enforces:
   - Nobody else than issue owner can upload a patch set
@@ skipping 23 matching lines @@
 
 # Hack out upload logging.info()
 upload.logging = logging.getLogger('upload')
 # Mac pylint choke on this line.
 upload.logging.setLevel(logging.WARNING)  # pylint: disable=E1103
 
 
 class Rietveld(object):
   """Accesses rietveld."""
   def __init__(self, url, email, password, extra_headers=None):
-    self.issue = None
     self.url = url
     if email and password:
       get_creds = lambda: (email, password)
       self.rpc_server = upload.HttpRpcServer(
             self.url,
             get_creds,
             extra_headers=extra_headers or {})
     else:
       self.rpc_server = upload.GetRpcServer(url, email)
     self._xsrf_token = None
@@ skipping 150 matching lines @@
         if retry >= (maxtries - 1):
           raise
         if not 'Name or service not known' in e.reason:
           # Usually internal GAE flakiness.
           raise
       # If reaching this line, loop again. Uses a small backoff.
       time.sleep(1+maxtries*2)
 
   # DEPRECATED.
   Send = get