Permissions for deleted users have broken links

If you delete a user via the REST API (i.e. http://<HOST>:7990/rest/api/1.0/admin/users?name=test), it does not clear out the user from the Project Permissions page.

Steps to reproduce:

1. Create a user, {{test}. for example.
2. Give the user permissions in a project.
3. Delete this user from the REST API. (i.e. http://<HOST>:7990/rest/api/1.0/admin/users?name=test).
4. Go to the permissions page for the project you set earlier.

You will notice that the user is shown as its username, rather than the display name, and clicking on the link will take you to a 404 page.