Description of problem:
When altering the view of a group under Issues > Alter display for: (group
name), it's possible to select non-employee viewable items and then save the
view as the global default. This results in the standard default view for
non-employees, not the customized one created by the RH employee. The system
should parse the available columns and refuse to save a global default view
(this is global default, not global employee default) if any columns have been
selected that cannot be viewed by customers.

Version-Release number of selected component (if applicable):
4.6

How reproducible:
Always

Steps to Reproduce:
1. Log in to IT as a RH employee
2. Go to Issues > Alter display for: (group name)
3. Add columns like "Pri" or "PS" and save as global default view
4. Non-RH users will see the standard default instead of the newly customized
view, as it contains columns they have no access to.
  
Actual results:
The system allows saving of non-customer viewable columns as the global default.
Customers don't get the custom view created by the RH employee because of this.

Expected results:
The system should reject attempts to save global default views that contain
non-customer viewable fields. Perhaps we should color code the items or "*" them
to let people know they're internal only fields?

Additional info: