remote-viewer-connect: Keep the 'dialog' window on top
    
    Otherwise, in kiosk mode, it'll be hidden from user.
    
    Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1459800
    
    Signed-off-by: Victor Toso <victortoso@redhat.com>
    Acked-by: Eduardo Lima (Etrunko) <etrunko@redhat.com>