Merge pull request #48 from Liwb5/develop

fix bug in gin layer when activation function is None

pgl/layers/conv.py

@@ -239,6 +239,7 @@ def gin(gw,
                              bias_attr=fluid.ParamAttr(name="%s_b_0" % name))
 
     output = fluid.layers.batch_norm(output)
+    if activation is not None:
         output = getattr(fluid.layers, activation)(output)
 
     output = fluid.layers.fc(output,