Update BatchNorm.md

caffe2fluid/doc/BatchNorm.md

@@ -17,7 +17,7 @@ layer {
 ```
 
 
-### [paddle.fluid.layers.batch_norm](http://paddlepaddle.org/documentation/docs/zh/1.3/api_cn/layers_cn.html#permalink-36-batch_norm)
+### [paddle.fluid.layers.batch_norm](http://paddlepaddle.org/documentation/docs/zh/1.4/api_cn/layers_cn.html#permalink-36-batch_norm)
 ```python
 paddle.fluid.layers.batch_norm(
     input,