Remove other v2 import in text_cls

fluid/text_classification/clouds/scdb_parallel_executor.py

 import unittest
 import contextlib
+import paddle
 import paddle.fluid as fluid
-import paddle.v2 as paddle
 import numpy as np
 import sys
 import time

fluid/text_classification/clouds/scdb_single_card.py

 import unittest
 import contextlib
+import paddle
 import paddle.fluid as fluid
-import paddle.v2 as paddle
 import numpy as np
 import sys
 import time

fluid/text_classification/nets.py

@@ -2,8 +2,8 @@ import sys
 import time
 import numpy as np
 
+import paddle
 import paddle.fluid as fluid
-import paddle.v2 as paddle
 
 
 def bow_net(data,

fluid/text_classification/utils.py

@@ -3,8 +3,8 @@ import sys
 import time
 import numpy as np
 
+import paddle
 import paddle.fluid as fluid
-import paddle.v2 as paddle
 
 
 def to_lodtensor(data, place):