Allow custom statsd port and host (for migration back to Bucky on 8126); fix restart on config update

I broke config file restart notification in a previous commit, this fixes it again.

Allow statsd port and host combo (defaults do not change). This allows us to use the local Bucky instance on the monitoring server. The issue with the collectd statsd implementation is that it uses a per-node prefix, which in turn can be limiting due to graphites maximum key name length.