du would exit early, when encountering an inaccessible directory

du would exit early, when encountering an inaccessible directory
Reported by Mike Frysinger, in
http://article.gmane.org/gmane.comp.gnu.core-utils.bugs/8831
* tests/du/inacc-dest: New test, based on an example from Mike Frysinger.
* tests/chgrp/no-x: Remove the "fts_read failed: ..."
diagnostic from the expected output when using native fdopendir.
* tests/chmod/no-x: Likewise.
* tests/du/no-x: Likewise.