update on Wayland and the installer

Summary: don't do anything.

Wayland by default is a goal for F24 Workstation 
(https://fedoraproject.org/wiki/Changes/WaylandByDefault), and if all 
goes right, then the Workstation live installer will be running on 
Wayland. We don't need to do anything for that to happen. We should keep 
an eye out for anything that might be going weird with anaconda running 
on Wayland (any of the places where we use Gdk functions directly 
deserve a look), but that's it.

For non-live media, the consensus is to just leave things the way they 
are for F24. X is not going away, and X is still necessary as a fallback 
for certain cases, so for boot.iso/netinst just keep using X. We can 
give this a closer look post-F24. If we do decide to switch to Wayland 
post-F24, that would mean at the least swapping out metacity for 
gnome-shell running in kiosk mode (like how gnome-initial-setup runs).