Hided CommTrack roles in mobile worker settings tab.

Should use Django template comments instead of HTML comments to prevent unnecessary processing of template tags inside the comment, and to prevent the commented HTML from being sent to the client. Also, it's a good idea to include a comment about why this section of code was commented. For example:

```html
{% comment "CommTrack user roles are not doing anything for now" %}
 <form class="form form-horizontal"
       method="post"
       action="{% url "update_user_data" domain couch_user.user_id %}">
 ...
 </form>
{% endcomment %}
```