B04004 - naming polymorph potions

Provide a chance for the player to name a polymorph potion if you dip
something into it and nothing happens.
Also fix several places in dipping and drinking potions where the HUP cheat
would allow you to use the potion a 2nd time, made more important since
the polymorph sequence includes what is currently a unique message.

src/potion.c

@@ -311,7 +311,8 @@ ghost_from_bottle()
 /* "Quaffing is like drinking, except you spill more."  -- Terry Pratchett
  */
 int
-dodrink() {
+dodrink()
+{
 	register struct obj *otmp;
 	const char *potion_descr;
 
@@ -375,6 +376,7 @@ register struct obj *otmp;
 {
 	int retval;
 
+	otmp->in_use = TRUE;
 	nothing = unkn = 0;
 	if((retval = peffects(otmp)) >= 0) return(retval);
 
@@ -1547,6 +1549,7 @@ dodip()
 		pline("That is a potion bottle, not a Klein bottle!");
 		return 0;
 	}
+	potion->in_use = TRUE;		/* assume it will be used up */
 	if(potion->otyp == POT_WATER) {
 		boolean useeit = !Blind;
 		if (useeit) (void) Shk_Your(Your_buf, obj);
@@ -1632,11 +1635,13 @@ dodip()
 			makeknown(POT_POLYMORPH);
 			useup(potion);
 			prinv((char *)0, obj, 0L);
+			return 1;
 		} else {
 			pline("Nothing seems to happen.");
-			useup(potion);
+			goto poof;
 		}
 	    }
+	    potion->in_use = FALSE;	/* didn't go poof */
 	    return(1);
 	} else if(obj->oclass == POTION_CLASS && obj->otyp != potion->otyp) {
 		/* Mixing potions is dangerous... */
@@ -1821,6 +1826,7 @@ dodip()
 	    }
 	    if (obj->age > 1000L) {
 		pline("%s %s full.", Yname2(obj), otense(obj, "are"));
+		potion->in_use = FALSE;	/* didn't go poof */
 	    } else {
 		You("fill %s with oil.", yname(obj));
 		check_unpaid(potion);	/* Yendorian Fuel Tax */
@@ -1835,6 +1841,7 @@ dodip()
 	    return 1;
 	}
 
+	potion->in_use = FALSE;		/* didn't go poof */
 	if ((obj->otyp == UNICORN_HORN || obj->otyp == AMETHYST) &&
 	    (mixture = mixtype(obj, potion)) != 0) {
 		boolean more_than_one = potion->quan > 1;