Bug 1559975 - Make config/ lint with 'py2' and 'py3' r=catlee

Depends on D36091

Differential Revision: https://phabricator.services.mozilla.com/D36092

config/pythonpath.py

@@ -2,6 +2,8 @@
 # License, v. 2.0. If a copy of the MPL was not distributed with this
 # file, You can obtain one at http://mozilla.org/MPL/2.0/.
 
+from __future__ import absolute_import
+from __future__ import print_function
 """
 Run a python script, adding extra directories to the python path.
 """