R788 - bones corpses shouldn't all be human

u.umonnum was used to create the corpse in a bones file.  However, unless
you're polymorphed and manage to actually die in that form, u.umonnum
refers to a role monster, which all have M2_HUMAN set, so they're all
human.  Even if the role monsters were mutated dynamically when the game
starts, the problem would still exist, just in a different form.
Use urace to determine the corpse type instead.

doc/fixes34.1

@@ -91,6 +91,7 @@ monsters should not repeatedly try to teleport on noteleport levels
 crocodiles legs are not designed for kicking open doors, chests, et al.
 walls of one of the luckstone locations in minend-3 were diggable
 minetn-6 could place downstairs in a cut-off location
+corpses in bones files don't retain their role characteristic
 
 
 Platform- and/or Interface-Specific Fixes