Add merge test for issue #2893, handle merge info for portions of a tree not checked out due to insufficient authz.
Add merge test for issue #2893, handle merge info for portions of a tree not
checked out due to insufficient authz.

* subversion/tests/cmdline/merge_tests.py
  (mergeinfo_and_skipped_paths): Expand test coverage.
  (test_list): Set mergeinfo_and_skipped_paths as XFail until issue #2893
  is fixed.

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion