sched: fix a find_busiest_group buglet

In one of the group load balancer patches:

	commit 408ed06
	Author: Peter Zijlstra <a.p.zijlstra@chello.nl>
	Date:   Fri Jun 27 13:41:28 2008 +0200
	Subject: sched: hierarchical load vs find_busiest_group

The following change:

-               if (max_load - this_load + SCHED_LOAD_SCALE_FUZZ >=
+               if (max_load - this_load + 2*busiest_load_per_task >=
                                        busiest_load_per_task * imbn) {

made the condition always true, because imbn is [1,2].
Therefore, remove the 2*, and give the it a fair chance.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched.c

@@ -3344,7 +3344,7 @@ find_busiest_group(struct sched_domain *sd, int this_cpu,
 		} else
 			this_load_per_task = cpu_avg_load_per_task(this_cpu);
 
-		if (max_load - this_load + 2*busiest_load_per_task >=
+		if (max_load - this_load + busiest_load_per_task >=
 					busiest_load_per_task * imbn) {
 			*imbalance = busiest_load_per_task;
 			return busiest;