Fix: IT Problem page didn't show all related items

In the only_related_to function we only check if
  * tested element have related contact
  * if the source problem have related contact
  * if related impacts have related contact
but we didn't test if host of current critical service have related
contact.

Here I've add the ability to check if host of the service have related
contact and should be displayed.
Add forgotten line
Check for admin