R363 - can't drown breathless monsters

- if you're polymorphed into an eel, you were able to drown things like xorns
- also, fix the tombstone message when an eel drowns you, it was basing the
message on your location, not the eel's location

src/mhitu.c

@@ -1158,8 +1158,9 @@ do_stone:
 		    } else if(u.ustuck == mtmp) {
 			if (is_pool(mtmp->mx,mtmp->my) && !Swimming
 			    && !Amphibious) {
-			    boolean moat = (levl[u.ux][u.uy].typ != POOL) &&
-				(levl[u.ux][u.uy].typ != WATER) &&
+			    boolean moat =
+				(levl[mtmp->mx][mtmp->my].typ != POOL) &&
+				(levl[mtmp->mx][mtmp->my].typ != WATER) &&
 				!Is_medusa_level(&u.uz) &&
 				!Is_waterlevel(&u.uz);