Adding both for branch preflight

bin/cbuildbot_config.py

 # Copyright (c) 2010 The Chromium OS Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """Dictionary of configuration types for cbuildbot.
 
 Each dictionary entry is in turn a dictionary of config_param->value.
 
 config_param's:
 board -- The board of the image to build.
@@ skipping 42 matching lines @@
   'smoke_bvt' : True,
   'overlays': 'private',
 }
 config['x86-mario-pre-flight-branch'] = {
   'board' : 'x86-mario',
   'uprev' : True,
   'master' : True,
   'important' : False,
   'unittests' : True,
   'smoke_bvt' : True,
+  'overlays': 'both',
 }
 config['x86_agz_bin'] = {
   'board' : 'x86-agz',
   'uprev' : True,
   'master' : False,
   'important' : False,
   'unittests' : True,
   'smoke_bvt' : True,
 }
 config['x86_dogfood_bin'] = {
@@ skipping 45 matching lines @@
   'unittests' : False,
 }
 config['arm_generic_bin'] = {
   'board' : 'arm-generic',
   'uprev' : True,
   'master' : False,
   'important' : False,
   'hostname' : 'codg175.jail',
   'unittests' : False,
 }