Respect path prefix in influx output uri (#3224)

plugins/outputs/influxdb/influxdb.go

@@ -53,9 +53,7 @@ type InfluxDB struct {
 }
 
 var sampleConfig = `
-  ## The HTTP or UDP URL for your InfluxDB instance.  Each item should be
-  ## of the form:
-  ##   scheme "://" host [ ":" port]
+  ## The full HTTP or UDP URL for your InfluxDB instance.
   ##
   ## Multiple urls can be specified as part of the same cluster,
   ## this means that only ONE of the urls will be written to each interval.