graphite: make sure we aggregate min/max/count properly

The default aggregator in graphite will make metrics ending with 'min'
to be aggregated by their minimum which seems to make sense for long
series.  Similary 'max' are aggregated by 'max' and 'counts' by sum.

Previously, any min/max metrics under the `stats` hierarchy were
aggregated with sum which is not that nice.

Change-Id: I4f6ecb0378114b2fb155b19c8e25dfa270515266
Note: rules are proceeded in order, first match win.
graphite: tweak statsd aggregation

Following upstream documentation tweak statsd aggregation following
upstream documentation at:

https://github.com/etsy/statsd/blob/master/docs/graphite.md

This DOES NOT affect existing metrics.  We probably want to adjust
existing one.

Change-Id: I39dfce78bd48be97d091230c6e8d50e08e27b819
Merge "graphite: make sure we aggregate min/max/count properly" into production
Merge "graphite: tweak statsd aggregation" into production