net_sched: Bug in netem reordering

Not now, but it looks you are correct. q->qdisc is NULL until another
additional qdisc is attached (beside tfifo). See 50612537.
The following patch should work.

From: Hagen Paul Pfeifer <hagen@jauu.net>

netem: catch NULL pointer by updating the real qdisc statistic

Reported-by: Vijay Subramanian <subramanian.vijay@gmail.com>
Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>