Avoid using predictable temporary filenames based on "tempfile".

* subversion/libsvn_wc/diff_editor.c
  (wrap_ensure_empty_file): Use svn_io_open_unique_file3.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1482973 13f79535-47bb-0310-9956-ffa450edef68
subversion/libsvn_client/import.c
  (svn_client_import5): Remove unused variable.


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1482974 13f79535-47bb-0310-9956-ffa450edef68