Invoking aria_pack breaks backups

--source include/have_aria.inc

CREATE TABLE t1 (a INT) ENGINE=Aria TRANSACTIONAL=1;

INSERT INTO t1 VALUES (1),(2);

FLUSH TABLE t1;

--exec $MARIA_PACK -s $MARIADB_DATADIR/test/t1

SELECT * FROM t1;

--let $bk= $MYSQLTEST_VARDIR/bk

--evalp BACKUP SERVER TO '$bk'

--rmdir $bk

DROP TABLE t1;

mysqltest: At line 9: query 'BACKUP SERVER TO '$bk'' failed: HA_ERR_NOT_A_TABLE (130): Error 130 reading the header of ./test/t1.MAI

CREATE TABLE t1 (a INT) ENGINE=Aria TRANSACTIONAL=1;

INSERT INTO t1 VALUES (1),(2);

FLUSH TABLE t1;

--exec $MARIA_PACK -s $MARIADB_DATADIR/test/t1

SELECT * FROM t1;

--let $targetdir= $MYSQLTEST_VARDIR/tmp/backup

--disable_result_log

--exec $XTRABACKUP --defaults-file=$MYSQLTEST_VARDIR/my.cnf --backup --target-dir=$targetdir

--exec $XTRABACKUP --prepare --target-dir=$targetdir

--source include/restart_and_restore.inc

--enable_result_log

SELECT * FROM t1;

DROP TABLE t1;

mysqltest: At line 17: query 'SELECT * FROM t1' failed: ER_FILE_NOT_FOUND (1017): Can't find file: './test/t1.MAI' (errno: 2 "No such file or directory")