结算时如有库存不足的商品，显示库存不足商品种类数量。 code review by LZF.

@@ -26,6 +26,8 @@ var navHammer,
 
 var isRefreshByDelete = window.cookie('_yoho-cart-refreshByDelete') === 'true' ? true : false;
 
+var lowStockCount = 0;
+
 
 loading.showLoadingMask();
 
@@ -93,8 +95,8 @@ function shouldLowStocks() {
 
     $lowStocks.each(function(idx, item) {
         if ($(item).parent().parent().parent().siblings('.checkbox').hasClass('icon-cb-checked')) {
+            lowStockCount += 1;
             result = true;
-            return false;
         }
     });
 
@@ -185,8 +187,9 @@ if ($('.freebie').length > 0) {
 }
 
 $('.btn-balance').on('touchend', function() {
+    lowStockCount = 0;
     if (shouldLowStocks()) {
-        tip.show('所选商品中含有库存不足的商品');
+        tip.show('所选商品中有' + lowStockCount + '种库存不足的商品');
         return false;
     }