use detected insert point as header during update if no parent item exists

fixes crash when updating the last album in the queue

src/bin/empc.c

@@ -2839,6 +2839,7 @@ queue_list_handler(Eina_Value *value, Eina_Bool update)
                        Empd_Empdd_Song *a, *b;
 
                        parent = elm_genlist_item_parent_get(next);
+                       if (!parent) parent = next;
                        a = elm_object_item_data_get(prev);
                        b = elm_object_item_data_get(parent);
                        /* check whether the previous album can be merged with the next one */