Ensure that buffer contents are random across jobs as well

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
diff --git a/io_u.c b/io_u.c
index 16c98b1..a87c58e 100644
--- a/io_u.c
+++ b/io_u.c
@@ -1450,7 +1450,7 @@
 	io_u->buf_filled_len = 0;
 
 	if (!td->o.zero_buffers)
-		fill_random_buf(io_u->buf, max_bs);
+		fill_random_buf(&td->buf_state, io_u->buf, max_bs);
 	else
 		memset(io_u->buf, 0, max_bs);
 }