MDEV-27534: mariabackup: missing line in the compress_qpress.result

This commit adds the missing line to the .result file for compress_qpress
(in the mariabackup test suite).

mysql-test/suite/mariabackup/compress_qpress.result

@@ -3,6 +3,7 @@ INSERT INTO t VALUES(1);
 # xtrabackup backup
 INSERT INTO t VALUES(2);
 # xtrabackup prepare
+db.opt.qp
 t.frm.qp
 t.ibd.qp
 # shutdown server