Flip the switch to make the merge code resposible for the merge notifications.

* subversion/libsvn_client/merge.c
  (HANDLE_NOTIFY_FROM_MERGE): Apply the switch, using this temporary macro.

* subversion/tests/cmdline/merge_tests.py
  (single_file_replace_style_merge_capability): Expect single file merges now
    to also report 'R'eplacements instead of 'D'elete+'A'dd.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1440083 13f79535-47bb-0310-9956-ffa450edef68