fix according to comment

python/paddle/v2/__init__.py

@@ -28,7 +28,7 @@ import pooling
 import inferencer
 import networks
 import py_paddle.swig_paddle as api
-import batch
+import minibatch
 
 __all__ = [
     'optimizer', 'layer', 'activation', 'parameters', 'init', 'trainer',
@@ -46,4 +46,4 @@ def init(**kwargs):
 
 
 infer = inferencer.infer
-batch = batch.batch
+batch = minibatch.batch