"refix the python logic"

python/paddle/v2/framework/framework.py

@@ -20,10 +20,10 @@ class Variable(object):
 
         if name is None:
             name = Variable._unique_var_name_()
-        try:
-            self.desc = self.block.desc.find_var(name)
-            is_new_var = False
-        except core.EnforceNotMet:
+        is_new_var = False
+        self.desc = self.block.desc.find_var(name)
+
+        if self.desc is None:
             self.desc = self.block.desc.var(name)
             is_new_var = True
 

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

@@ -51,7 +51,7 @@ class TestProgram(unittest.TestCase):
         sum_op_desc.set_input("Y", ["b1"])
         sum_op_desc.set_output("Out", ["out2"])
 
-        target = block.new_var("out2")
+        target = block.var("out2")
 
         expect_ops = [
             "mul", "elementwise_add", "fill_constant", "elementwise_add_grad",