The `error` and `timeout` attributes in QEMUMonitorProtocol are
not used, so this delete them.

Signed-off-by: Wainer dos Santos Moschetta <wainersm@redhat.com>
Reviewed-by: John Snow <jsnow@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20191227134101.244496-6-wainersm@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>