Merge pull request #4103 from wanghaoshuang/pad_op

Fix unitest of pad_op

python/paddle/v2/framework/tests/test_pad_op.py

@@ -22,7 +22,7 @@ class TestPadOp(OpTest):
         self.check_output()
 
     def test_check_grad_normal(self):
-        self.check_grad(['X'], 'Out')
+        self.check_grad(['X'], 'Out', max_relative_error=0.006)
 
     def initTestCase(self):
         self.shape = (16, 16)