I dug in and now understand these settings.  Here's how it works:

* `prefixStats` is is applied to the internal statistics that get pushed.
* `graphite.legacyNamespace` (default: true) is a flag that turns off the subsequent settings
  * `graphite.globalPrefix` gets prepended to everything, including internal statistics
  * `graphite.prefix{Timer|Gauge|Set|Counter}` gets appended to the globalPrefix for respective metrics except for the internal statistics.
  * `graphite.globalSuffix` becomes the last part of a metric name, including internal statistics.

I'm going to create eight corresponding settings in BF that should correspond with these settings in statsd.  I'm on the fence about what to do about `prefixStats`.  That will be useful for separating the internal stats by statsd host, so it probably shouldn't be a single setting in BF.

Does anybody thing we should be processing/ingesting the internal metrics from statsd?  Maybe that belongs in another PR.