Log NavigationTiming data to Ganglia

This change follos up the addition of Ganglia support to StatsD in I79f0d05c5;
it configures the StatsD instance of hafnium to log NavigationTiming data to
ganglia, using the spoofed host 'client-side'. Thus configured, the StatsD
instance on hafnium is no longer generic, but appropriate only for client-side
data. Consequently I moved it from 'misc::graphite::statsd' into the navtiming
class itself.

Change-Id: Ib643edc9fd30c9a79d6756bce35df523844cab43