old bug report: unchanging iron golem still rehumanizes

Calling rehumanize directly when u.mh > 0 doesn't consider Unchanging
(perhaps it should?).  But, it's probably better to call losehp anyway.
Also, part of a buglist item: .5PD didn't affect rust trap damage on iron golem

doc/fixes34.3

@@ -63,6 +63,7 @@ allow a crystal ball to detect mimics via ']'
 prevent boulder option from accepting a symbol that matches a monster symbol
 traveling while standing on a trap would sometime step in the wrong direction
 avoid traveling into water/lava, using usual running rules
+unchanging iron golem would still rehumanize in a rust trap
 
 
 Platform- and/or Interface-Specific Fixes