Remove logging and metrics from builder alerts code

infra/services/builder_alerts/alert_builder.py

Index: infra/services/builder_alerts/alert_builder.py
diff --git a/infra/services/builder_alerts/alert_builder.py b/infra/services/builder_alerts/alert_builder.py
index b1bd63e945b578f57db538c4a9331d0535a33605..5d03d80eb39f1261b42af018f93c954bb251586e 100644
--- a/infra/services/builder_alerts/alert_builder.py
+++ b/infra/services/builder_alerts/alert_builder.py
@@ -348,7 +348,6 @@ def alerts_for_master(cache, master_url, master_json, old_alerts,
       active_builds.append(build)
 
   def process_builder(builder_name):
-    logging.debug('Thread for builder %s has started', builder_name)
     try:
       if builder_name_filter and builder_name_filter not in builder_name:
         return None
@@ -369,16 +368,11 @@ def alerts_for_master(cache, master_url, master_json, old_alerts,
       # Put all exception text into an exception and raise that so it doesn't
       # get eaten by the multiprocessing code.
       raise Exception(''.join(traceback.format_exception(*sys.exc_info())))
-    finally:
-      logging.debug('Thread for builder %s has finished', builder_name)
 
   pool = multiprocessing.dummy.Pool(processes=jobs)
-  logging.debug('Processing all builders via thread pool')
   builder_alerts = pool.map(process_builder, master_json['builders'].keys())
-  logging.debug('Closing all threads in builder thread pool')
   pool.close()
   pool.join()
-  logging.debug('Joined all threads in builder thread pool')
 
   alerts = []
   for alert in builder_alerts: