Remove promote script from editor/build and put it under tools (where it really belongs)

tools/promote.py

 #!/usr/bin/env python
 #
 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 # Dart Editor promote tools.
 
 import imp
 import optparse
 import os
 import subprocess
 import sys
 import time
 import urllib
+import bots.bot_utils as bot_utils
 
 from os.path import join
 
-DART_PATH = os.path.abspath(os.path.join(__file__, '..', '..', '..'))
-BOT_UTILS = os.path.abspath(os.path.join(
-    DART_PATH,  'tools', 'bots', 'bot_utils.py'))
-
-bot_utils = imp.load_source('bot_utils', BOT_UTILS)
+DART_PATH = os.path.abspath(os.path.join(__file__, '..', '..'))
 
 def BuildOptions():
   usage = """usage: %prog promote [options]
   where:
     promote - Will promote builds from raw/signed locations to release
               locations.
 
     Example: Promote revision r29962 on dev channel:
         python editor/build/promote.py promote --channel=dev --revision=29962
   """
@@ skipping 133 matching lines @@
   promote('latest')
 
 def Gsutil(cmd, throw_on_error=True):
   gsutilTool = join(DART_PATH, 'third_party', 'gsutil', 'gsutil')
   return bot_utils.run([sys.executable, gsutilTool] + cmd,
                        throw_on_error=throw_on_error)
 
 
 if __name__ == '__main__':
   sys.exit(main())