[Checkins] [zopefoundation/zope.security] d726f9: Work around pypa/virtualenv#1555

[Michael Howitz]

  Branch: refs/heads/sphinx-py23
  Home:   https://github.com/zopefoundation/zope.security
  Commit: d726f9d7d4a65a01c47001be74ab67ae8ac13454
      https://github.com/zopefoundation/zope.security/commit/d726f9d7d4a65a01c47001be74ab67ae8ac13454
  Author: Michael Howitz <mh at gocept.com>
  Date:   2020-02-11 (Tue, 11 Feb 2020)

  Changed paths:
    M .travis.yml

  Log Message:
  -----------
  Work around pypa/virtualenv#1555