[Checkins] [zopefoundation/zope.configuration] 89d701: Do not break when running the tests from a wheel.

[Michael Howitz]

  Branch: refs/heads/fix-ztk-tests
  Home:   https://github.com/zopefoundation/zope.configuration
  Commit: 89d7014caf2e0d02b67c08df39b3e3ec46fc7064
      https://github.com/zopefoundation/zope.configuration/commit/89d7014caf2e0d02b67c08df39b3e3ec46fc7064
  Author: Michael Howitz <mh at gocept.com>
  Date:   2019-02-09 (Sat, 09 Feb 2019)

  Changed paths:
    M CHANGES.rst
    M src/zope/configuration/tests/test_docs.py

  Log Message:
  -----------
  Do not break when running the tests from a wheel.

The wheel does neither include `setup.py` nor the `docs` dir.
So omit the documentation tests when no `setup.py` can be found.
This should fix the tests in ZTK.