add May 2004 trunk patch to the branch

Bug Report:
>> Status of the doppelganger (neutral): Level 13 HP 1433(1433) AC 5.
>> [See the HPs!! ]

Michael:
> I used a debugger and traced this massive hit point growth
> to this line in mon.c, function newcham(). (I watched the mhp
> jump from 58 to 567 with this one calculation!
>> Ah, I see that this problem is fixed in the trunk but still present in
>> the branch. This seems serious/abusive enough to warrant the fix to be
>> applied to the branch too, doesn't it?

Pat:
>      I don't think it's all that important but you're welcome to
> extract and adapt the patch if you like.

doc/fixes34.4

@@ -25,6 +25,7 @@ be consistent with use of "removing" rather than "lifting" for encumber
 	messages associated with taking things out of a bag of holding
 cursed scroll of destroy armor damaging cursed armor didn't adjust attributes
 add passive() flag that indicates uwep was destroyed during the turn
+polymorphed or shapechanged monster sometimes got erroneous hit points
 calculate weight of corpses on special levels correctly
 Sting could trigger premature display of orcs during savegame restore
 Sting now glows light blue again