Revert "efl_ui_layout: call efl_del instead of efl_unref when text part does not exist"

This reverts commit cced5487c8.

This patch was pushed just to silence warning without fixing the problem and doing
something that was incorrect (coupling an efl_del with an efl_ref).

Reviewed-by: Marcel Hollerbach <mail@marcel-hollerbach.de>
Differential Revision: https://phab.enlightenment.org/D8429

src/lib/elementary/efl_ui_layout.c

@@ -2780,7 +2780,7 @@ elm_layout_text_set(Eo *obj, const char *part, const char *text)
    if (!efl_isa(part_obj, EFL_TEXT_INTERFACE) ||
        !efl_isa(part_obj, EFL_UI_LAYOUT_PART_CLASS))
      {
-        efl_del(part_obj);
+        efl_unref(part_obj);
         return EINA_FALSE;
      }