[Checkins] [zopefoundation/RestrictedPython] d03645: Fix as suggested by @stephan-hof.

[GitHub]

  Branch: refs/heads/fix-full-write-guard
  Home:   https://github.com/zopefoundation/RestrictedPython
  Commit: d03645beec22218da1813ef62ab18866b35c13ad
      https://github.com/zopefoundation/RestrictedPython/commit/d03645beec22218da1813ef62ab18866b35c13ad
  Author: Michael Howitz <mh at gocept.com>
  Date:   2017-03-27 (Mon, 27 Mar 2017)

  Changed paths:
    M src/RestrictedPython/Guards.py

  Log Message:
  -----------
  Fix as suggested by @stephan-hof.