ocfs2: don't use flush_scheduled_work()

flush_scheduled_work() is deprecated and scheduled to be removed.

* cancel_delayed_work() + flush_schedule_work() ->
  cancel_delayed_work_sync().

* flush qs->qs_work directly on exit instead.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Joel Becker <joel.becker@oracle.com>
Cc: Mark Fasheh <mfasheh@suse.com>
diff --git a/fs/ocfs2/cluster/heartbeat.c b/fs/ocfs2/cluster/heartbeat.c
index 52c7557..892e2de 100644
--- a/fs/ocfs2/cluster/heartbeat.c
+++ b/fs/ocfs2/cluster/heartbeat.c
@@ -307,8 +307,7 @@
 
 static void o2hb_disarm_write_timeout(struct o2hb_region *reg)
 {
-	cancel_delayed_work(&reg->hr_write_timeout_work);
-	flush_scheduled_work();
+	cancel_delayed_work_sync(&reg->hr_write_timeout_work);
 }
 
 static inline void o2hb_bio_wait_init(struct o2hb_bio_wait_ctxt *wc)