Enabling Root User For GNOME Display Manager

[Rahul Sundaram <sundaram fedoraproject org>]

Hi

I have add this often requested information to

https://fedoraproject.org/wiki/Enabling_Root_User_For_GNOME_Display_Manager

Also added it as a reference to

https://fedoraproject.org/wiki/Documentation_Desktop_Beat

Please review the changes and edit the wiki if necessary. Thank you for
your feedback.

Rahul