The default displayer for users is failing with guest

Steps to reproduce:
(note: this issues does not reproduce only in AWM)

1. Go to "More Applications" from "Application" panel
2. Click on "Create your own"
3. Start creating an app
4. Add a "User" field
5. Click on "Next" button
6. Add your newly added field on the livetable by adding it from the list
7. After you save the app, add a new entry
8. Go to the app home page
9. The column corresponing to the "User" field is displayed correctly when logged in but it runs into a NPE when viewing as guest.

The issue does not reproduce on 6.2.4.
It seems that between 6.2.4 and 6.3 there were some changes made on displayer_users.vm which lead to this issue.

Stack trace