Allow the use of auth and credentials in opentsdb

public/app/plugins/datasource/opentsdb/datasource.js

@@ -13,6 +13,8 @@ function (angular, _, dateMath) {
     this.type = 'opentsdb';
     this.url = instanceSettings.url;
     this.name = instanceSettings.name;
+    this.withCredentials = instanceSettings.withCredentials;
+    this.basicAuth = instanceSettings.basicAuth;
     this.supportMetrics = true;
 
     // Called once per panel (graph)
@@ -71,6 +73,15 @@ function (angular, _, dateMath) {
         url: this.url + '/api/query',
         data: reqBody
       };
+      
+      if (this.basicAuth || this.withCredentials) {
+        options.withCredentials = true;
+      }
+      if (this.basicAuth) {
+        options.headers = {
+          "Authorization": this.basicAuth
+        };
+      }
 
       // In case the backend is 3rd-party hosted and does not suport OPTIONS, urlencoded requests
       // go as POST rather than OPTIONS+POST