sched: Add missing call to calc_load_exit_idle()

Azat Khuzhin reported high loadavg in Linux v3.6

After checking the upstream scheduler code, I found Peter's commit:

  5167e8d5417b sched/nohz: Rewrite and fix load-avg computation -- again

not fully applied, missing the call to calc_load_exit_idle().

After that idle exit in sampling window will always be calculated
to non-idle, and the load will be higher than normal.

This patch adds the missing call to calc_load_exit_idle().

Signed-off-by: Charles Wang <muming.wq@taobao.com>
Cc: stable@kernel.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1345449754-27130-1-git-send-email-muming.wq@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>

Conflicts:

	kernel/time/tick-sched.c