roll_webrtc.py: Improve no-op roll message.

tools/roll_webrtc.py

 #!/usr/bin/env python
 # Copyright 2015 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 argparse
 import collections
 import logging
 import os
 import re
@@ skipping 284 matching lines @@
     libjingle_current = self._GetDepsCommitInfo(deps, LIBJINGLE_PATH)
 
     # Find ToT revisions.
     webrtc_latest = self._GetCommitInfo(WEBRTC_PATH)
     libjingle_latest = self._GetCommitInfo(LIBJINGLE_PATH)
 
     self._UpdateDep(deps_filename, WEBRTC_PATH, webrtc_latest)
     self._UpdateDep(deps_filename, LIBJINGLE_PATH, libjingle_latest)
 
     if self._IsTreeClean():
-      logging.debug('Tree is clean - no changes detected.')
+      print 'The latest revision is already rolled for WebRTC and libjingle.'
       self._DeleteRollBranch()
     else:
       self._UpdateReadmeFile(LIBJINGLE_README, libjingle_latest.commit_position)
       description = _GenerateCLDescription(webrtc_current, libjingle_current,
                                            webrtc_latest, libjingle_latest)
       logging.debug('Committing changes locally.')
       self._RunCommand(['git', 'add', '--update', '.'])
       self._RunCommand(['git', 'commit', '-m', description])
       logging.debug('Uploading changes...')
       self._RunCommand(['git', 'cl', 'upload', '-m', description],
@@ skipping 110 matching lines @@
   if args.abort:
     return autoroller.Abort()
   elif args.wait_for_trybots:
     return autoroller.WaitForTrybots()
   else:
     return autoroller.PrepareRoll(args.dry_run, args.ignore_checks,
                                   args.no_commit, args.close_previous_roll)
 
 if __name__ == '__main__':
   sys.exit(main())