fix undefined callback in sounds

public/src/modules/sounds.js

@@ -8,18 +8,14 @@ define('sounds', ['buzz'], function(buzz) {
 	var eventSoundMapping;
 	var files;
 
-	socket.on('event:sounds.reloadMapping', loadMapping);
-
-	function loadMapping(callback) {
-		callback = callback || function() {};
+	socket.on('event:sounds.reloadMapping', function() {
 		socket.emit('modules.sounds.getMapping', function(err, mapping) {
 			if (err) {
 				return app.alertError('[sounds] Could not load sound mapping!');
 			}
 			eventSoundMapping = mapping;
-			callback();
 		});
-	}
+	});
 
 	function loadData(callback) {
 		socket.emit('modules.sounds.getData', function(err, data) {