Fix the perpetual haste cheat.

Rogue V3 allowed the player to gain perpetual haste by quaffing a
potion of haste while already hasted.  This is supposed to remove the
haste effect and cause temporary paralysis.

Super-Rogue removed haste correctly, but gave confusing messages.

srogue/rings.c

@@ -84,7 +84,6 @@ ring_on(void)
 				}
 				else {
 					add_haste(FALSE);
-					msg("You find yourself moving must faster.");
 				}
 			when R_GIANT:				/* to 24 */
 				him->s_ef.a_str = MAXSTR;