Revision 1588772

Implement an initial fix for issue #4480 "Mergeinfo overwritten on successive
merges".

As noted in the code this patch might make this code report out of date in a
few cases where we should allow a commit, but this is much safer than not
reporting out of date where we should.

As far as I can tell this check matches how we do things in the repos/fs
commit api, so I hope somebody with more knowledge of these apis can
confirm that this is the right fix to close issue #4480.

* subversion/mod_dav_svn/repos.c
  (do_out_of_date_check): Implement an additional out of date check for
    directory changes to catch the issue #4480 problem.

* subversion/tests/cmdline/commit_tests.py
  (commit_mergeinfo_ood): Remove XFail marker.