Make the 'svn cp WC URL' code properly calculate whether mixed revisions will
be committed as replacement or as addition.

* subversion/libsvn_client/commit_util.c
  (harvest_status_callback): In copy mode, check for mixed-revision and switched
    base node if they exist in the parent directory and if they do issue an
    explicit delete.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1553539 13f79535-47bb-0310-9956-ffa450edef68