elm: Fix obvious warning (leak / typo)

warning: ignoring return value of function declared with
warn_unused_result attribute [-Wunused-result]

Thanks GCC for pointing out the leak.

src/lib/elementary/elc_fileselector.c

@@ -1697,7 +1697,7 @@ cancel:
    eo_unref(obj);
    eo_unref(it_data->model);
    eo_unref(it_data->parent_model);
-   eina_stringshare_add(it_data->parent_path);
+   eina_stringshare_del(it_data->parent_path);
    free(it_data);
 }