Following up on r1553367, extend testcase to show that proplist is
still broken for DAV even though a single propget for a revision property
works correctly now.

* subversion/tests/cmdline/prop_tests.py
  (xml_unsafe_author): Extend test.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1553374 13f79535-47bb-0310-9956-ffa450edef68