Disabled users should not be available for selection when replacing authors

STEPS TO REPRODUCE

1. Login as Admin
2. Create an user (e.g. U1)
3. Login as U1
4. Create a page with some content (e.g. Pag1)
5. Login as Admin
6. Go to Administer Wiki > Users & Rights > Users
7. Click 'Disable', then 'Delete'
8. Observe the available user selections in the 'New Author' drop-down
9. Select U1
10. Click 'Delete'
11. Go to page previously created by U1 and observe the message below the title: 'Last modified by...'

EXPECTED RESULTS

Once the user (U1) is disabled, it does not appear anymore in the 'New Author' drop-down in available selections.

ACTUAL RESULTS

The user (U1) is displayed and available for selection. After being selected (and deleted), the message 'Last modified by...' from the page created by it does not contain a link to user's profile anymore.