Move 'buildbot.tac' and 'buildbot' files to a common directory.

masters/buildbot.tac

Index: masters/buildbot.tac
diff --git a/masters/buildbot.tac b/masters/buildbot.tac
new file mode 100644
index 0000000000000000000000000000000000000000..b7d70d5c0a7503f83956a418daf2fd31f43d0381
--- /dev/null
+++ b/masters/buildbot.tac
@@ -0,0 +1,17 @@
+# Copyright 2016 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.
+
+"""Common twistd configuration for buildbot.
+
+Use this with:
+  twistd -y buildbot.tac -d path/to/master
+"""
+
+import os
+
+from twisted.application import service
+from buildbot.master import BuildMaster
+
+application = service.Application('buildmaster')
+BuildMaster(os.getcwd(), 'master.cfg').setServiceParent(application)