Fix get_latest_build to return actual latest build

Tools/TestResultServer/handlers/buildershandler.py

 # Copyright (C) 2013 Google Inc. All rights reserved.
 #
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 # notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 # copyright notice, this list of conditions and the following disclaimer
@@ skipping 72 matching lines @@
 
 def get_latest_build(build_data):
     cached_builds = []
     if 'cachedBuilds' in build_data:
         cached_builds = build_data['cachedBuilds']
 
     current_builds = build_data['currentBuilds']
 
     latest_cached_builds = set(cached_builds) - set(current_builds)
     if len(latest_cached_builds) != 0:
-        latest_build = list(latest_cached_builds)[-1]
+        latest_cached_builds = sorted(list(latest_cached_builds))
+        latest_build = latest_cached_builds[-1]
     elif len(current_builds) != 0:
         latest_build = current_builds[0]
     else:
         basedir = build_data['basedir'] if 'basedir' in build_data else 'current builder'
         logging.info('No cached or current builds for %s', basedir)
         return None
 
     return latest_build
 
 
@@ skipping 61 matching lines @@
             buildbot_data = fetch_buildbot_data(MASTERS)
             try:
                 memcache.set('buildbot_data', buildbot_data)
             except ValueError, err:
                 logging.error(str(err))
 
         if callback:
             buildbot_data = callback + '(' + buildbot_data + ');'
 
         self.response.out.write(buildbot_data)