local-display: don't use wayland with gnome-initial-setup
    
    We haven't yet decided to use gnome-initial-setup on wayland.
    Before we can, we need to create a wayland based session file
    for it anyway.
    
    This commit makes sure we properly fall back to X11 for
    gnome-initial-setup.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=745139