Requeue io_u flags fix

We need to clear IO_U_F_FLIGHT and set IO_U_F_FREE in requeue.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/io_u.c b/io_u.c
index 53e57b4..372f46a 100644
--- a/io_u.c
+++ b/io_u.c
@@ -211,6 +211,9 @@
 {
 	struct io_u *__io_u = *io_u;
 
+	__io_u->flags |= IO_U_F_FREE;
+	__io_u->flags &= ~IO_U_F_FLIGHT;
+
 	list_del(&__io_u->list);
 	list_add_tail(&__io_u->list, &td->io_u_requeues);
 	td->cur_depth--;