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

masters/master.tryserver.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.builders_pools import BuildersPools
 from master.factory import annotator_factory
 from buildbot.schedulers.basic import SingleBranchScheduler
@@ skipping 19 matching lines @@
   'Mojo Android Builder Tests (dbg) Try',
 ]
 
 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)
 
 c['logCompressionLimit'] = False
 c['projectName'] = ActiveMaster.project_name
 c['projectURL'] = config.Master.project_url
 # Must come before AutoSetupMaster().
 c['buildbotURL'] = ActiveMaster.buildbot_url
 
 # Associate the slaves to the manual builders. The configuration is in
 # slaves.cfg.
 slaves = slaves_list.SlavesList('slaves.cfg', 'MojoTryServer')
@@ skipping 13 matching lines @@
     templates=['../master.chromium/templates'],
     enable_http_status_push=ActiveMaster.is_production_host)
 
 
 # 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