fix bad code in python

Author: guochaorong

python/paddle/fluid/layers/metric.py

@@ -64,10 +64,6 @@ def auc(input, label, curve='ROC', num_thresholds=200):
     topk_indices = helper.create_tmp_variable(dtype="int64")
     topk_out, topk_indices = nn.topk(input, k=k)
     auc_out = helper.create_tmp_variable(dtype="float32")
-    if correct is None:
-        correct = helper.create_tmp_variable(dtype="int64")
-    if total is None:
-        total = helper.create_tmp_variable(dtype="int64")
     helper.append_op(
         type="accuracy",
         inputs={

python/paddle/fluid/tests/unittests/test_dynrnn_gradient_check.py

@@ -30,9 +30,6 @@ def update(self, val):
         assert val.dtype == self.ex.dtype
         self.cur = val
 
-    def ex(self):
-        return self.ex
-
     def next(self):
         self.ex = self.cur
         self.cur = None