[K12OSN] Removing Shutdown and Restart from Login Screen

[R. Scott Belford]

Aloha Y'all

I have been trying to figure out what to edit to remove the shutdown and 
restart options from our server that operates as a workstation.  I have 
seen that on K12LTSP5 it has been removed.  This lab is still running 
4.x, and if a mischievous student chooses to reboot the lab, they can. 
Can anyone point me to the file I need to edit.  /etc/X11/gdm.conf does 
not seem to have what I am looking for, but I may have missed it.

--scott