sched: change active_load_balance_cpu_stop to use h_nr_running

Date	Sun, 18 Aug 2013 16:25:21 +0800

We should only avoid do the active load balance when there is no
cfs type task. If just use rq->nr_running, it is possible for the
source cpu has multiple rt task, while zero cfs task, so that it
would confuse the active load balance function that try to move,
but find no task it could move.

Signed-off-by: Lei Wen <leiwen@marvell.com>
Signed-off-by: Paul Reioux <reioux@gmail.com>