Make sure to install setuptools less then version 36.0.0 to avoid module six not found issue (#341)

Change-Id: I7ba64be56354be5a03e6f6b349990af6b662e457

Author: jerryshao

Diff for: .travis.yml

@@ -30,8 +30,8 @@ before_install:
   - sudo apt-get -y install python3-pip python-dev
   - sudo apt-get -y install libkrb5-dev
   - sudo apt-get -y remove python-setuptools
-  - pip install --user --upgrade pip setuptools
-  - pip3 install --user --upgrade pip setuptools
+  - pip install --user --upgrade pip "setuptools < 36"
+  - pip3 install --user --upgrade pip "setuptools < 36"
   - pip install --user codecov cloudpickle
   - pip3 install --user cloudpickle