removed ECMA6 js code

sites/all/themes/custom/edlptheme/assets/scripts/main.js

@@ -128,7 +128,7 @@
 
       // entrees
       // TODO: center the entrees menu
-       
+
     };
 
 
@@ -970,12 +970,11 @@
         var promise = this.audio.play();
         // console.log('promise', promise);
         if (promise !== undefined) {
-          promise.catch(error => {
+          promise.catch(function(error){
               // Auto-play was prevented
               // Show a UI element to let the user manually start playback
               console.warn('autoplay failed, ask for playing', error);
-
-          }).then(() => {
+          }).then(function(){
               // Auto-play started
               console.log('autoplay succeed');
           });