Fix #1674045 workaround for bootloader case
    
    The initial implementation here has a problem if we spot the
    'successful' screen briefly, then the system reboots normally,
    reaches the bootloader and proceeds past it all within 10
    seconds; in this case we'll never actually spot the bootloader
    and do our stuff. This tweak should continue through the code
    block immediately if the bootloader shows up during the ten
    seconds, otherwise check again for the 'successful' screen and
    reboot.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>