Replaces scraping each node's service port with the dedicated Prometheus
listener each node now advertises. Nodes started without -metricsPort
advertise 0 and are skipped, so nothing is ever fetched from a
client-facing port.
Endpoints are deduplicated by address because a combined "weed server"
advertises one listener for all of its components; series are attributed
by metric name, which already identifies the component.
Chris Lu
a6e07181b2