--replace-all so we don't accum variables with git watchlist use

git_cl_hooks.py

 # Copyright (c) 2009 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.
 
 import os
 import re
 import subprocess
 import sys
 
 import breakpad
@@ skipping 40 matching lines @@
   commit = (hook_name == 'pre-cl-dcommit')
 
   # Create our options based on the command-line args and the current checkout.
   options = ChangeOptions(commit=commit, upstream_branch=upstream_branch)
 
   # Apply watchlists on upload.
   if not commit:
     watchlist = watchlists.Watchlists(options.change.RepositoryRoot())
     files = [f.LocalPath() for f in options.change.AffectedFiles()]
     watchers = watchlist.GetWatchersForPaths(files)
-    Backquote(['git', 'config', '--add',
+    Backquote(['git', 'config', '--replace-all',
                'rietveld.extracc', ','.join(watchers)])
 
   # Run the presubmit checks.
   if presubmit_support.DoPresubmitChecks(options.change,
                                          options.commit,
                                          options.verbose,
                                          sys.stdout,
                                          sys.stdin,
                                          options.default_presubmit,
                                          options.may_prompt):
     sys.exit(0)
   else:
     sys.exit(1)