WebRTC: Set the right path to clean_symlinks.py

scripts/slave/recipe_modules/webrtc/resources/cleanup_symlinks.py

 #!/usr/bin/env python
 # Copyright 2016 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.
 
 """Script that deletes all symlinks created by setup_links.py in a checkout."""
 
 import os
 import subprocess
 import sys
 
 
 def main(args):
   if len(args) != 1:
-    print >> sys.stderr, 'Please specify a single directory as an argument.'
+    print >> sys.stderr, ('Please specify a single directory as an argument, '
+                          'which points to the checkout root (dir above src/).'
     return 1
 
-  checkout_dir = args[0]
-  if not os.path.isdir(checkout_dir):
-    print 'Cannot find any directory at %s. Skipping cleaning.' % checkout_dir
+  checkout_root = args[0]
+  if not os.path.isdir(checkout_root):
+    print 'Cannot find any directory at %s. Skipping cleaning.' % checkout_root
     return 0
 
-  setup_links_file = os.path.join(checkout_dir, 'setup_links.py')
-  if not os.path.isfile(setup_links_file):
-    print 'Cannot find %s. Incomplete checkout?' % setup_links_file
-    return 1
-  else:
-    print 'Cleaning up symlinks in %s' % checkout_dir
+  setup_links_file = os.path.join(checkout_root, 'src', 'setup_links.py')
+  if os.path.isfile(setup_links_file):
+    print 'Cleaning up symlinks in %s' % checkout_root
     subprocess.check_call([sys.executable, setup_links_file, '--clean-only'],
-                          cwd=checkout_dir)
-    return 0
-
+                          cwd=checkout_root)
+  return 0
 
 
 if __name__ == '__main__':
   sys.exit(main(sys.argv[1:]))