Fix CI and enhance gitignore

Author: reyoung

.gitignore

@@ -27,7 +27,6 @@ third_party/
 cmake-build-*
 
 # generated while compiling
-python/paddle/v2/fluid/core.so
 paddle/pybind/pybind.h
 CMakeFiles
 cmake_install.cmake

python/paddle/fluid/.gitignore

@@ -1 +1,2 @@
 proto
+core.so

python/paddle/fluid/layers/layer_function_generator.py

@@ -130,7 +130,7 @@ def generate_layer_fn(op_type):
     o_name = not_intermediate_outputs[0].name
     intermediate_output_names = [output.name for output in intermediate_outputs]
 
-    def infer_and_check_dtype(op_proto, **kwargs):
+    def infer_and_check_dtype(op_proto, *args, **kwargs):
         """
         This function performs the sanity check for dtype and
         instance type.
@@ -141,6 +141,10 @@ def infer_and_check_dtype(op_proto, **kwargs):
             val = kwargs.pop(name, [])
             if not isinstance(val, list) and not isinstance(val, tuple):
                 val = [val]
+            if len(val) == 0:
+                val = [args[0]]
+                args = args[1:]
+
             for each in val:
                 if not isinstance(each, Variable):
                     raise ValueError("input of {0} must be variable".format(
@@ -158,7 +162,7 @@ def infer_and_check_dtype(op_proto, **kwargs):
     def func(*args, **kwargs):
         helper = LayerHelper(op_type, **kwargs)
 
-        dtype = infer_and_check_dtype(op_proto, **kwargs)
+        dtype = infer_and_check_dtype(op_proto, *args, **kwargs)
 
         inputs = dict()
         for ipt in op_proto.inputs: