fix(testdata): fixed query in default grafana data source

public/app/plugins/datasource/grafana/datasource.ts

 ///<reference path="../../../headers/common.d.ts" />
 
+import _ from 'lodash';
+
 class GrafanaDatasource {
 
   /** @ngInject */
   constructor(private backendSrv) {}
 
   query(options) {
-    return this.backendSrv.get('/api/metrics/test', {
-      from: options.range.from.valueOf(),
-      to: options.range.to.valueOf(),
-      scenario: 'random_walk',
-      interval: options.intervalMs,
-      maxDataPoints: options.maxDataPoints
+    return this.backendSrv.post('/api/tsdb/query', {
+      from: options.range.from.valueOf().toString(),
+      to: options.range.to.valueOf().toString(),
+      queries: [
+        {
+          "refId": "A",
+          "scenarioId": "random_walk",
+          "intervalMs": options.intervalMs,
+          "maxDataPoints": options.maxDataPoints,
+        }
+      ]
+    }).then(res => {
+
+      var data = [];
+      if (res.results) {
+        _.forEach(res.results, queryRes => {
+          for (let series of queryRes.series) {
+            data.push({
+              target: series.name,
+              datapoints: series.points
+            });
+          }
+        });
+      }
+
+      return {data: data};
     });
   }