Configures the first serial port to allow a serial console connection.

def _set_serial_console(self):
        """
        Configures the first serial port to allow a serial console connection.
        """

        # activate the first serial port
        yield from self._modify_vm("--uart1 0x3F8 4")

        # set server mode with a pipe on the first serial port
        pipe_name = self._get_pipe_name()
        args = [self._vmname, "--uartmode1", "server", pipe_name]
        yield from self.manager.execute("modifyvm", args)