Issue #1901476 by caiosba | mstef: Fixed Uncaught TypeError: Cannot read...

Issue #1901476 by caiosba | mstef: Fixed Uncaught TypeError: Cannot read property 'command' of undefined in ajax.js.

misc/ajax.js

@@ -396,7 +396,7 @@ Drupal.ajax.prototype.success = function (response, status) {
   Drupal.freezeHeight();
 
   for (var i in response) {
-    if (response[i]['command'] && this.commands[response[i]['command']]) {
+    if (response.hasOwnProperty(i) && response[i]['command'] && this.commands[response[i]['command']]) {
       this.commands[response[i]['command']](this, response[i], status);
     }
   }