Emergency check fix for the scroll locker

Fix to stop main.js from completely bugging out on any page that isn't challengeType: 0

public/js/main_0.0.3.js

@@ -365,7 +365,7 @@ $(document).ready(function() {
         });
     }
 
-    if($('.scroll-locker') != undefined){
+    if($('.scroll-locker').html() != undefined){
         function lockTop(initOff){
             $(window).scroll(function() {
                 if ($(window).width() >= 992) {