contint: let us configure statsd for Zuul

This simple patch let us generate a /etc/default/zuul init script
configuration file that would later let us run Zuul with STATSD_HOST and
STATSD_PORT which will make it send statsd notification.

Change-Id: I2a8e6daa9c85a12fbedba6ed6e59031f974f9deb
Set proper RRD storage types for vhtcpd ganglia.

This is the third try at getting the right graphs to show in ganglia for
the vhtcpd metrics. This change removes my feeble attempt at computing
deltas within the collector in favor of giving ganglia the proper type
hints via the `slope` attribute for each metric.

Metrics that we want to store as the difference between the previous and
current sample (RRD's GUAGE type) are hinted using `slope=positive`.
Metrics that only change on service restart as hinted using
`slope=zero`. Metrics that we want to record the actual metric value are
hinted using `slope=both`.

See also:
http://codeblog.majakorpi.net/post/16281432462/ganglia-xml-slope-attribute

Change-Id: I4a3382146608a4bc7d84527a464a3d6894a51f90
Merge "contint: let us configure statsd for Zuul" into production