Deleted User Has Entry In Membership table

Deleting users does not remove the entry associated to the user in the cwd_membership table.

Steps to replicate:

1. Install JIRA with User Internal Directory
2. create a new user into the Internal Directory
3. run queries to check if the user exist in cwd_user and cwd_membership table:

   SELECT * FROM cwd_user where user_name='<user_name>';
   SELECT * FROM cwd_membership where child_name='<user_name>';
   

4. delete the user from JIRA UI
5. run the same SQL query against the database and the user will have the entries in the cwd_membership table:

   SELECT user_name,active,directory_id FROM cwd_user where user_name='testuser1';
   Empty set (0.00 sec)
   

   and

   mysql> SELECT * FROM cwd_membership where child_name='testuser1';
   +-------+-----------+----------+-----------------+------------+-------------+-------------------+------------+------------------+--------------+
   | ID    | parent_id | child_id | membership_type | group_type | parent_name | lower_parent_name | child_name | lower_child_name | directory_id |
   +-------+-----------+----------+-----------------+------------+-------------+-------------------+------------+------------------+--------------+
   | 10010 |     10002 |    10010 | GROUP_USER      | NULL       | jira-users  | jira-users        | testuser1  | testuser1        |            1 |
   | 10011 |     10010 |    10010 | GROUP_USER      | NULL       | testgroup   | testgroup         | testuser1  | testuser1        |            1 |
   +-------+-----------+----------+-----------------+------------+-------------+-------------------+------------+------------------+--------------+
   

In the JIRA UI, the users does not appear in any configuration. However, this seems to be affecting users that is migrating from other issues trackers. The expected behaviour is that the entries in cwd_membership will be remove after the user is deleted.