Remove vestigial Stackdriver dependency

examples/stats/exporter/prometheus.js

@@ -1,20 +1,3 @@
-/**
- * Copyright 2018, OpenCensus Authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-
  /**
  * Copyright 2018, OpenCensus Authors
  *
@@ -155,16 +138,6 @@ lineReader.on("line", function(line) {
   startNanoseconds = endNanoseconds;
 });
 
-/**
- * The default export interval is 60 seconds.
- * The thread with must live for at least the interval past any
- * metrics that must be collected, or some risk being lost if they are recorded
- * after the last export.
- */
-setTimeout(function() {
-  console.log("Completed.");
-}, 60 * 1000);
-
 /**
  * Takes a line and process it.
  * @param {string} line The line to process