Add a new buildbot-tool generator for master configs

scripts/tools/buildbot_tool_templates/master_source_cfg.py

Index: scripts/tools/buildbot_tool_templates/master_source_cfg.py
diff --git a/masters/master.client.mojo/master_source_cfg.py b/scripts/tools/buildbot_tool_templates/master_source_cfg.py
similarity index 75%
copy from masters/master.client.mojo/master_source_cfg.py
copy to scripts/tools/buildbot_tool_templates/master_source_cfg.py
index 7887715652bdc99df877fbdeadb9d78883f0aa6a..324e2294caad03df6968b67a23d1842444ac74b5 100644
--- a/masters/master.client.mojo/master_source_cfg.py
+++ b/scripts/tools/buildbot_tool_templates/master_source_cfg.py
@@ -2,11 +2,13 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
+# This file is used by scripts/tools/buildbot-tool to generate master configs.

[agable, 2014/12/09 21:13:24]

I'm not convinced of the need for a master_source_config.py. I think it makes it
harder to see what's going on all in one place. I'd just put it directly in
master.cfg.

[Dirk Pranke, 2014/12/09 21:32:01]

OK. I tend to agree, but I wasn't sure if it would be more or less confusing to
hack on the templates too much here.

+
 from master import gitiles_poller
 
 
 def Update(config, active_master, c):
   master_poller = gitiles_poller.GitilesPoller(
-      'https://chromium.googlesource.com/external/mojo')
+      '%(git_repo_url)s')
 
   c['change_source'].append(master_poller)