禁止库存不足的商品被勾选. code review by XWG

@@ -43,6 +43,11 @@ $('.cart-goods').on('touchstart', '.checkbox', function() {
     var goodsList = [],
         goodInfo = {};
 
+    if (!$this.hasClass('icon-cb-checked') && $this.siblings('.info').find('.low-stocks').length > 0) {
+        tip.show('库存不足，无法购买');
+        return false;
+    }
+
     goodInfo.goods_type = cartType;
     goodInfo.selected = $this.hasClass('icon-cb-checked') ? 'N' : 'Y';
     goodInfo.product_sku = id;