sched: nominate preferred wakeup cpu, fix

Andrew Morton reported:

> kernel/sched.c: In function 'schedule':
> kernel/sched.c:3679: warning: 'active_balance' may be used uninitialized in this function
>
> This warning is correct - the code is buggy.

In sched.c load_balance_newidle, there's real potential use of
uninitialised variable - fix it.

Signed-off-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

kernel/sched.c

@@ -3670,7 +3670,7 @@ redo:
 	}
 
 	if (!ld_moved) {
-		int active_balance;
+		int active_balance = 0;
 
 		schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]);
 		if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER &&