Remove stale references to the blink_presubmit bot.

PRESUBMIT.py

 # 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.
 
 """Top-level presubmit script for Chromium.
 
 See http://dev.chromium.org/developers/how-tos/depottools/presubmit-scripts
 for more details about the presubmit API built into depot_tools.
 """
 
@@ skipping 2039 matching lines @@
 
 def GetTryServerMasterForBot(bot):
   """Returns the Try Server master for the given bot.
 
   It tries to guess the master from the bot name, but may still fail
   and return None.  There is no longer a default master.
   """
   # Potentially ambiguous bot names are listed explicitly.
   master_map = {
       'chromium_presubmit': 'tryserver.chromium.linux',
-      'blink_presubmit': 'tryserver.chromium.linux',
       'tools_build_presubmit': 'tryserver.chromium.linux',
   }
   master = master_map.get(bot)
   if not master:
     if 'linux' in bot or 'android' in bot or 'presubmit' in bot:
       master = 'tryserver.chromium.linux'
     elif 'win' in bot:
       master = 'tryserver.chromium.win'
     elif 'mac' in bot or 'ios' in bot:
       master = 'tryserver.chromium.mac'
@@ skipping 20 matching lines @@
   results.extend(input_api.canned_checks.CheckTreeIsOpen(
       input_api,
       output_api,
       json_url='http://chromium-status.appspot.com/current?format=json'))
 
   results.extend(input_api.canned_checks.CheckChangeHasBugField(
       input_api, output_api))
   results.extend(input_api.canned_checks.CheckChangeHasDescription(
       input_api, output_api))
   return results