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

masters/master.chromium.swarm/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.
 
 from buildbot.scheduler import Scheduler
 from buildbot.schedulers import timed
 from buildbot.status import mail
@@ skipping 11 matching lines @@
 ActiveMaster = master_site_config.ChromiumSwarm
 
 # This is the dictionary that the buildmaster pays attention to. We also use
 # a shorter alias to save typing.
 c = BuildmasterConfig = {}
 
 # '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
 
-config.DatabaseSetup(c, require_dbconfig=ActiveMaster.is_production_host)
+config.DatabaseSetup(c)
 
 ####### CHANGESOURCES
 
 # Polls config.Master.trunk_url for changes
 master_poller = gitiles_poller.GitilesPoller(
     'https://chromium.googlesource.com/chromium/src')
 
 c['change_source'] = [master_poller]
 
 ####### SCHEDULERS
@@ skipping 115 matching lines @@
     public_html="../master.chromium/public_html",
     templates=['../master.chromium/templates'],
     tagComparator=master_poller.comparator,
     enable_http_status_push=ActiveMaster.is_production_host)
 
 
 ####### PROJECT IDENTITY
 
 c['projectName'] = ActiveMaster.project_name
 c['projectURL'] = config.Master.project_url