force delete from place if there is no corresponding object in placex

This might happen for nameless landuse/natural objects that are added to place
during initial import but then dropped when being copied to placex.
If they later receive a name, thus becoming valid, then place_insert should
delete the orphan object in place and reinsert it. If they are large enough,
the place_delete trigger prevents them from being removed. The additional
update fools the delete trigger.