[Checkins] [zopefoundation/RestrictedPython] afb869: Clean up Travis config (#152)

[Michael Howitz]

  Branch: refs/heads/master
  Home:   https://github.com/zopefoundation/RestrictedPython
  Commit: afb869425cfe522564780d3ff11afc90c9ed4f8f
      https://github.com/zopefoundation/RestrictedPython/commit/afb869425cfe522564780d3ff11afc90c9ed4f8f
  Author: Michael Howitz <mh at gocept.com>
  Date:   2019-02-09 (Sat, 09 Feb 2019)

  Changed paths:
    M .travis.yml

  Log Message:
  -----------
  Clean up Travis config (#152)

* One Python 3.7 test is enough.
* The docs and lint tests do not produce coverage.