fix #H148 - applying a pickaxe doesn't respect pushweapon

From a bug report, applying a pick-axe will
wield it in place of the primary weapon but wouldn't update the alternate
weapon.  Make objects which become wielded when applied (pick, lamp, whip,
grappling hook, pole-arm) honor the pushweapon option (where the previously
wielded weapon becomes the alternate weapon without use of 'x' command) the
same as when explicitly wielded.  Old behavior matched the documentation,
but that seemed overly restrictive.

src/wield.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)wield.c	3.5	2006/06/16	*/
+/*	SCCS Id: @(#)wield.c	3.5	2006/07/14	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -465,14 +465,19 @@ const char *verb;	/* "rub",&c */
 	    verb, (obj->oclass == WEAPON_CLASS) ? "weapon" : "tool");
 	return FALSE;
     }
+
     if (uquiver == obj) setuqwep((struct obj *)0);
     if (uswapwep == obj) {
 	(void) doswapweapon();
 	/* doswapweapon might fail */
 	if (uswapwep == obj) return FALSE;
     } else {
+	struct obj *oldwep = uwep;
+
 	You("now wield %s.", doname(obj));
 	setuwep(obj);
+	if (flags.pushweapon && oldwep && uwep != oldwep)
+	    setuswapwep(oldwep);
     }
     if (uwep != obj) return FALSE;	/* rewielded old object after dying */
     /* applying weapon or tool that gets wielded ends two-weapon combat */