pids: Initialize leader_pid in init_task

This is cheap and no cost so we might as well.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

init/init_task.c

@@ -33,6 +33,7 @@ static struct signal_struct init_signals = {
 	},
 #endif
 	INIT_CPU_TIMERS(init_signals)
+	.leader_pid = &init_struct_pid,
 	INIT_PREV_CPUTIME(init_signals)
 };