engines/libaio: fix wrong setting of wait_start

Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/engines/libaio.c b/engines/libaio.c
index 12f3b36..f7e2f89 100644
--- a/engines/libaio.c
+++ b/engines/libaio.c
@@ -281,7 +281,7 @@
 			}
 			if (!wait_start) {
 				fio_gettime(&tv, NULL);
-				wait_start = 0;
+				wait_start = 1;
 			} else if (mtime_since_now(&tv) > 30000) {
 				log_err("fio: aio appears to be stalled, giving up\n");
 				break;