Mark basic_tests.py 38 as XFAIL if running DAV tests with a version of
HTTPd where mod_dav has an URL quoting bug.

See: https://issues.apache.org/bugzilla/show_bug.cgi?id=56480

* subversion/tests/cmdline/davautocheck.sh:
   Parse and export the HTTPd versions.

* subversion/tests/cmdline/svntest/main.py
  (__mod_dav_url_quoting_broken_versions): New; the list of HTTPd versions
   where mod_dav is known to have the bug described in PR 56480
  (is_mod_dav_url_quoting_broken): New predicate.
* subversion/tests/cmdline/basic_tests.py
  (special_paths_in_repos): Tag as XFail with the new predicate.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1639507 13f79535-47bb-0310-9956-ffa450edef68