Wait longer for console to appear after quitting Firefox
    
    A couple of tests failed in F31/Rawhide lately because quitting
    Firefox (running on a bare X server) took more than 10 seconds
    to get back to a console...not sure why, but it's not something
    we ought to waste a lot of time on, let's just bump the timeout.
    
    Signed-off-by: Adam Williamson <awilliam@redhat.com>