fixed misleading name of an action

front-ui/app/stores/cartStore.js

@@ -99,7 +99,7 @@ var takeItemOut = function(itemId) {
 
 */
 
-var setItemCount = function(item, count) {
+var addNItems = function(item, count) {
 
     var itemId = item.get('id');
      var state = states[itemId] || new ItemInCart({
@@ -290,8 +290,8 @@ AppDispatcher.register(function(payload) {
         case CartConstants.CONFIRM_DELIVERY:
             saveDeliveryDestination();
             break;
-        case CartConstants.SET_ITEM_COUNT:
-            setItemCount(action.item, action.count);
+        case CartConstants.ADD_N_ITEMS:
+            addNItems(action.item, action.count);
             break;
         default:
             return true;