ipntable: Fix typo in help text

Signed-off-by: Phil Sutter <phil@nwl.cc>

ip/ipntable.c

@@ -52,7 +52,7 @@ static void usage(void)
 
 		"PARMS := [ base_reachable MSEC ] [ retrans MSEC ] [ gc_stale MSEC ]\n"
 		"         [ delay_probe MSEC ] [ queue LEN ]\n"
-		"         [ app_probs VAL ] [ ucast_probes VAL ] [ mcast_probes VAL ]\n"
+		"         [ app_probes VAL ] [ ucast_probes VAL ] [ mcast_probes VAL ]\n"
 		"         [ anycast_delay MSEC ] [ proxy_delay MSEC ] [ proxy_queue LEN ]\n"
 		"         [ locktime MSEC ]\n"
 		);