Break config_default into master_site_configs.

masters/master.chromium.webrtc/master.cfg

 # 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.
 
 from buildbot.status import mail
 
 # These modules come from scripts/master, which must be in the PYTHONPATH.
 from master import master_utils
 from master import slaves_list
 
 import config
-ActiveMaster = config.Master.ChromiumWebRTC
+import master_site_config
+ActiveMaster = master_site_config.ChromiumWebRTC
 
 c = BuildmasterConfig = {}
 c['change_source'] = []
 c['schedulers'] = []
 c['builders'] = []
 c['status'] = []
 
 config.DatabaseSetup(c, require_dbconfig=ActiveMaster.is_production_host)
 
 import master_source_cfg
@@ skipping 42 matching lines @@
       extraRecipients=[ActiveMaster.from_address],
       mode='problem',
       relayhost=config.Master.smtp))
 
 # Do it at the end to override values set by AutoSetupMaster, the default is
 # too low. Must keep at least a few days worth of builds.
 c['buildHorizon'] = 3000
 c['logHorizon'] = 3000
 # Must be at least 2x the number of slaves.
 c['eventHorizon'] = 200