ADD CHECK leaves an orphaned .par file

drop database if exists orphan_par_test;

create database orphan_par_test;

use orphan_par_test;

drop table if exists t;

create table t(id int, d DATE NOT NULL, manual_override BOOL NOT NULL DEFAULT 0, primary key(id,d))

PARTITION BY RANGE COLUMNS (d) ( 

PARTITION p20161017 VALUES LESS THAN ('2016-10-18'),

PARTITION p20161018 VALUES LESS THAN ('2016-10-19'));

ALTER TABLE t ADD CHECK (b IN (0, 1));

drop database orphan_par_test;

MariaDB [orphan_par_test]> drop database orphan_par_test;

ERROR 1010 (HY000): Error dropping database (can't rmdir './orphan_par_test', errno: 39 "Directory not empty")

[ec2-user@ip-172-30-0-32 ~]$ sudo ls -l /var/lib/mysql/orphan_par_test/

total 4

-rw-rw---- 1 mysql mysql 48 Mar 28 19:01 #sql-32a_6.par