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

masters/master.client.mojo/master.cfg

 # Copyright 2014 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.
 
 # These modules come from scripts/master, which must be in the PYTHONPATH.
 from master import master_utils
 from master import slaves_list
 from master.factory import annotator_factory
 from buildbot.schedulers.basic import SingleBranchScheduler
 from buildbot.status.mail import MailNotifier
@@ skipping 20 matching lines @@
             'Mojo Android Builder Tests (dbg)',
             'Mojo Linux Perf']
 
 for builder_name in builders:
   c['builders'].append({
     'name': builder_name,
     'factory': m_annotator.BaseFactory('mojo'),
     'slavebuilddir': 'mojo',
   })
 
-config.DatabaseSetup(c, require_dbconfig=ActiveMaster.is_production_host)
+config.DatabaseSetup(c)
 
 import master_source_cfg
 
 master_source_cfg.Update(config, ActiveMaster, c)
 
 c['schedulers'].extend([
     SingleBranchScheduler(name='source',
                           branch='master',
                           treeStableTimer=60,
                           builderNames=builders)
@@ skipping 28 matching lines @@
 c['status'].append(MailNotifier(fromaddr=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