elasticsearch: default version to 5.x

public/app/plugins/datasource/elasticsearch/config_ctrl.ts

@@ -1,5 +1,3 @@
-///<reference path="../../../headers/common.d.ts" />
-
 import _ from 'lodash';
 
 export class ElasticConfigCtrl {
@@ -9,6 +7,7 @@ export class ElasticConfigCtrl {
   /** @ngInject */
   constructor($scope) {
     this.current.jsonData.timeField = this.current.jsonData.timeField || '@timestamp';
+    this.current.jsonData.esVersion = this.current.jsonData.esVersion || 5;
   }
 
   indexPatternTypes = [