Don't require a .dbconfig file on any masters.

masters/master.client.dart/master.cfg

 # -*- python -*-
 # ex: set syntax=python:
 
 # 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.
 
 # It has one job: define a dictionary named BuildmasterConfig. This
 # dictionary has a variety of keys to control different aspects of the
 # buildmaster. They are documented in docs/config.xhtml .
@@ skipping 25 matching lines @@
 
 MASTER_HOST = ActiveMaster.master_host
 WEB_STATUS = True
 MAIL_NOTIFIER = ActiveMaster.is_production_host
 GOOD_REVISIONS = ActiveMaster.is_production_host
 
 # This is the dictionary that the buildmaster pays attention to. We also use
 # a shorter alias to save typing.
 c = BuildmasterConfig = {}
 
-config.DatabaseSetup(c, require_dbconfig=ActiveMaster.is_production_host)
+config.DatabaseSetup(c)
 
 # 'slavePortnum' defines the TCP port to listen on. This must match the value
 # configured into the buildslaves (with their --master option)
 c['slavePortnum'] = ActiveMaster.slave_port
 
 slaves = slaves_list.SlavesList('slaves.cfg', 'Dart')
 
 annotator = annotator_factory.AnnotatorFactory()
 
 def setup_channel(channel):
@@ skipping 577 matching lines @@
 c['projectName'] = ActiveMaster.project_name
 c['projectURL'] = config.Master.project_url
 
 # the 'buildbotURL' string should point to the location where the buildbot's
 # internal web server (usually the html.Waterfall page) is visible. This
 # typically uses the port number set in the Waterfall 'status' entry, but
 # with an externally-visible host name which the buildbot cannot figure out
 # without some help.
 
 c['buildbotURL'] = ActiveMaster.buildbot_url