Add a regression test on property conflict details.

* subversion/tests/cmdline/prop_tests.py
  (dir_prop_conflict_details): New test.
  (test_list): Add dir_prop_conflict_details.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1558245 13f79535-47bb-0310-9956-ffa450edef68