[sysmon] Make PuppetRunSummary private

BUG=None
TEST=None

Change-Id: I883726a611f744f31a997db58b8cb011af8432b8
Reviewed-on: https://chromium-review.googlesource.com/421572
Commit-Ready: Allen Li <ayatane@chromium.org>
Tested-by: Allen Li <ayatane@chromium.org>
Reviewed-by: Aviv Keshet <akeshet@chromium.org>
diff --git a/scripts/sysmon/puppet_metrics.py b/scripts/sysmon/puppet_metrics.py
index 47bfc74..97ab1f7 100644
--- a/scripts/sysmon/puppet_metrics.py
+++ b/scripts/sysmon/puppet_metrics.py
@@ -40,7 +40,7 @@
     units=ts_mon.MetricsDataUnits.SECONDS)
 
 
-class PuppetRunSummary(object):
+class _PuppetRunSummary(object):
   """Puppet run summary information."""
 
   def __init__(self, summary_file):
@@ -87,7 +87,7 @@
 def get_puppet_summary():
   """Send Puppet run summary metrics."""
   try:
-    summary = PuppetRunSummary(LAST_RUN_FILE)
+    summary = _PuppetRunSummary(LAST_RUN_FILE)
   except Exception as e:
     logging.warning('Error loading Puppet run summary: %s', e)
   else: