Remove old stats from whisper

Over time, graphite seems to have acquired a range of keys that are no
longer updated and can be quite confusing when trying to find data.

This small cron job (cribbed from suggestions in [1]) should remove
all old data that hasn't been updated in nine months (this should be
long-enough to cover all manner of periodic jobs)

[1] http://stackoverflow.com/questions/9587161/how-to-cleanup-the-graphite-whispers-data

Change-Id: I598b9d370a337866e9086cbe0238569da70aa471

modules/graphite/manifests/init.pp

@@ -218,5 +218,15 @@ class graphite(
                     Vcsrepo['/opt/statsd']],
   }
 
+  # remove any stats that haven't been updated for ~9 months and
+  # remove empty dirs
+  cron { 'remove_old_stats':
+    user        => 'root',
+    hour        => '2',
+    minute      => '0',
+    command     => 'find /var/lib/graphite/storage/whisper -type f -mtime +270 -name \*.wsp -delete; find /var/lib/graphite/storage/whisper -depth -type d -empty -delete > /dev/null',
+    environment => 'PATH=/usr/bin:/bin:/usr/sbin:/sbin',
+  }
+
 }