Following up on r1440966, also handle file obstruction handling in the merge
from the file_openened function.

* subversion/libsvn_client/merge.c
  (merge_file_baton_t): Add fields to store conflicts and skips.
  (mark_dir_edited): Add comment.
  (mark_file_edited): Handle skips and tree conflicts on files.

  (merge_file_opened): Handle obstruction handling for changes, adds, deletes
    and persist the result in the baton. Or notify if we know the result for
    delete/add.

  (merge_file_changed,
   merge_file_added,
   merge_file_deleted): Replace obstruction check with simple baton readout.

  (merge_dir_opened): Tweak comment.

* subversion/tests/cmdline/merge_authz_tests.py
  (mergeinfo_and_skipped_paths): Expect detailed skip.

* subversion/tests/cmdline/merge_tests.py
  (merge_to_sparse_directories): Expect detailed skip.

* subversion/tests/cmdline/merge_tree_conflict_tests.py
  (tree_conflicts_merge_edit_onto_missing): Expect detailed skip.

* subversion/tests/cmdline/tree_conflict_tests.py
  (at_directory_external): Remove Wimp marker (added in r1440966)


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1441043 13f79535-47bb-0310-9956-ffa450edef68