Remove redundant code in word2vec readme (#798)

04.word2vec/README.cn.md

@@ -238,7 +238,7 @@ dream that one day <e>
 
 from __future__ import print_function
 
-import paddle as paddle
+import paddle
 import paddle.fluid as fluid
 import six
 import numpy

04.word2vec/index.cn.html

@@ -280,7 +280,7 @@ dream that one day <e>
 
 from __future__ import print_function
 
-import paddle as paddle
+import paddle
 import paddle.fluid as fluid
 import six
 import numpy