Add test for Issue #4300.

* subversion/tests/cmdline/update_tests.py
  (update_swapped_depth_dirs): New test.
  (test_list): Add update_swapped_depth_dirs.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1437096 13f79535-47bb-0310-9956-ffa450edef68