[Python-checkins] [python/cpython] 838398: Use `-W` option to Sphinx

[GitHub]

  Branch: refs/heads/docs-W
  Home:   https://github.com/python/cpython
  Commit: 838398fd340427bb56decb7b394e1f10b0f9b688
      https://github.com/python/cpython/commit/838398fd340427bb56decb7b394e1f10b0f9b688
  Author: Zachary Ware <zachary.ware at gmail.com>
  Date:   2017-03-26 (Sun, 26 Mar 2017)

  Changed paths:
    M .travis.yml

  Log Message:
  -----------
  Use `-W` option to Sphinx

Treat warnings as errors.