Remove duplicated imports in train_supervised.py

Summary: Pull Request resolved: https://github.com/facebookresearch/fastText/pull/524

Differential Revision: D9348102

Pulled By: EdouardGrave

fbshipit-source-id: 6fa88544517652f184254238d4129da9c5b734ce

python/doc/examples/train_supervised.py

@@ -11,7 +11,6 @@ from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
 from __future__ import unicode_literals
-from __future__ import division, absolute_import, print_function
 
 import os
 from fastText import train_supervised