Sporadic failure in storage_engine/trx.xa_recovery test

The test complains that the server failed to disappear upon shutdown /
wait_for_disconnect. Trying to solve the probably race condition by 
adding a wait before restart.

mysql-test/suite/storage_engine/trx/xa_recovery.test

@@ -56,10 +56,14 @@ XA PREPARE 'xa2';
 --connection default
 --enable_reconnect
 --append_file $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
-restart
+wait
 EOF
 --shutdown_server 0
 --source include/wait_until_disconnected.inc
+
+--append_file $MYSQLTEST_VARDIR/tmp/mysqld.1.expect
+restart
+EOF
 --source include/wait_until_connected_again.inc
 XA RECOVER;
 XA ROLLBACK 'xa1';