[NETEM]: report reorder percent correctly.

If you setup netem to just delay packets; "tc qdisc ls" will report
the reordering as 100%. Well it's a lie, reorder isn't used unless
gap is set, so just set value to 0 so the output of utility
is correct.
Signed-off-by: NStephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sched/sch_netem.c

@@ -429,7 +429,8 @@ static int netem_change(struct Qdisc *sch, struct rtattr *opt)
 	/* for compatiablity with earlier versions.
 	 * if gap is set, need to assume 100% probablity
 	 */
-	q->reorder = ~0;
+	if (q->gap)
+		q->reorder = ~0;
 
 	/* Handle nested options after initial queue options.
 	 * Should have put all options in nested format but too late now.