Fix bad sign on td_verror()

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
diff --git a/ioengines.c b/ioengines.c
index 7ab356a..f8c52e5 100644
--- a/ioengines.c
+++ b/ioengines.c
@@ -208,7 +208,7 @@
 	if (r >= 0)
 		io_u_mark_complete(td, r);
 	else
-		td_verror(td, -r, "get_events");
+		td_verror(td, r, "get_events");
 
 	dprint(FD_IO, "getevents: %d\n", r);
 	return r;