Robustify and tweak switch out of overview on GNOME boot
    
    This fails sometimes just because we're too early, or something.
    Also with GNOME Shell 41rc, alt-f1 no longer works to open and
    close the overview. super *does* seem to work in KDE these days,
    so let's switch from alt-f1 to super everywhere.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>