Fix gcl.py error introduced in r196786.

gcl.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.
 
 """\
 Wrapper script around Rietveld's upload.py that simplifies working with groups
 of files.
 """
 
@@ skipping 371 matching lines @@
     return self.SendToRietveld('/%d/description' % self.issue)
 
   def UpdateDescriptionFromIssue(self):
     """Updates self.description with the issue description from Rietveld."""
     self._desc = git_cl.ChangeDescription(
         self.SendToRietveld('/%d/description' % self.issue))
 
   def GetApprovingReviewers(self):
     """Returns the issue reviewers list from Rietveld."""
     return git_cl.get_approving_reviewers(
-        self.rietveld.get_issue_properties(self.issue, False))
+        self.RpcServer().get_issue_properties(self.issue, False))
 
   def AddComment(self, comment):
     """Adds a comment for an issue on Rietveld.
     As a side effect, this will email everyone associated with the issue."""
     return self.RpcServer().add_comment(self.issue, comment)
 
   def PrimeLint(self):
     """Do background work on Rietveld to lint the file so that the results are
     ready when the issue is viewed."""
     if self.issue and self.patchset:
@@ skipping 1064 matching lines @@
       raise
     print >> sys.stderr, (
         'AppEngine is misbehaving and returned HTTP %d, again. Keep faith '
         'and retry or visit go/isgaeup.\n%s') % (e.code, str(e))
     return 1
 
 
 if __name__ == "__main__":
   fix_encoding.fix_encoding()
   sys.exit(main(sys.argv[1:]))