Reseting password via cli doesn't work when adminUserName has been changed

[ScharfViktor]

community request https://central.owncloud.org/t/resetting-or-recreating-admin-user/49643

ocis version: 6.0.0

steps:

• run ocis binary
• change admin userName to adminNew
• stop ocis
• go to the terminal and reset password ocis/bin/ocis idm resetpassword

Expected: password is changed
Actual: password is not changed

Resetting password for user 'uid=admin,ou=users,o=libregraph-idm'.
Enter new password: 
Re-enter new password: 
Failed to update admin password: entry does not exist
Password for user 'uid=admin,ou=users,o=libregraph-idm' updated.