Merge pull request #242 from lcy-seso/fix_travis

fix travis.

.travis.yml

@@ -17,7 +17,7 @@ addons:
       - python-pip
       - python2.7-dev
 before_install:
-  -  pip install -U virtualenv pre-commit pip
+  -  sudo pip install -U virtualenv pre-commit pip
   -  docker pull paddlepaddle/paddle:latest
 script:
   -  .travis/precommit.sh