fix so that google analytics script are cached

(cherry picked from commit ddeba41638)

public/app/core/services/analytics.ts

@@ -7,7 +7,11 @@ export class Analytics {
   constructor(private $rootScope, private $location) {}
 
   gaInit() {
-    $.getScript('https://www.google-analytics.com/analytics.js'); // jQuery shortcut
+    $.ajax({
+      url: 'https://www.google-analytics.com/analytics.js',
+      dataType: 'script',
+      cache: true,
+    });
     var ga = ((<any>window).ga =
       (<any>window).ga ||
       function() {