fix issue #843 - vampire revival sequencing

Reported by Umbire:
|You kill SpaceMannSpiff!  SpaceMannSpiff puts on a dwarvish cloak.
|SpaceMannSpiff puts on a dwarvish iron helm.
|The seemingly dead SpaceMannSpiff suddenly transforms and rises as
| a Vampire.

This was tough to reproduce but I finally managed it.  The issue
text mentions that it was fixed by copperwater in xNetHack with
commit 8c4af50f0aa3e72522f3eb98df039ff25c2a1ea0 to the repository
for that variant.  My attempt to cherry-pick that failed--I'm not
even sure whether it should have been expected to work--and some of
the code has been impinged upon by changes, so I ended up applying
the contents of that commit manually.

The commit changes how/when monsters put on new armor rather than
anything directly related to vampires.  Circumstances similar to
the example above now yield:
|You kill SpaceMannSpiff!
|The seemingly dead SpaceMannSpiff suddenly transforms and rises as
| a Vampire.
on one turn, then on the next turn the revived vampire produces:
|SpaceMannSpiff puts on a dwarvish cloak.

My test case only had one item of interest; I assume that the second
item of armor gets worn on a subsequent turn rather than at the same
time as the first one.

Fixes #843

doc/fixes3-7-0.txt

@@ -1988,6 +1988,9 @@ vampire shapeshifting in a door (pr #794 by entrez)
 split "act_on_act" into separate function (pr #777 by argrath)
 unnecessary null-check on parsesymbols() (pr #793 by argrath)
 split cleaning-up on gd_move() into separate function (pr #791 by argrath)
+from xNetHack:  better handling for monsters putting on equipment; fixes
+	issue #843:  "Mon dies.  Mon puts on <armor>.  The seemingly dead Mon
+	rises as a vampire."
 
 
 Code Cleanup and Reorganization