gold and touchstones

Implement Pat's suggestion of allowing even identified touchstones
to test gold, removing the getobj hack recently added.  This actually
brings the touchstone a bit more in line with the data.base entry.

src/invent.c

@@ -968,12 +968,7 @@ register const char *let,*word;
 		}
 		if(ilet == def_oc_syms[COIN_CLASS]) {
 			if (!usegold) {
-			    if (!strncmp(word, "rub on ", 7)) {
-				/* the dangers of building sentences... */
-				You("cannot rub gold%s.", word + 3);
-			    } else {
-				You("cannot %s gold.", word);
-			    }
+			    You("cannot %s gold.", word);
 			    return(struct obj *)0;
 #ifndef GOLDOBJ
 			} else if (!allowgold) {