Add the qemu path to the hypervisor conf data

        :param instance: Hypervisor instance

def add_qemu_path(self, instance):
        """
        Add the qemu path to the hypervisor conf data

        :param instance: Hypervisor instance
        """
        tmp_conf = {'qemu_path': self.old_top[instance]['qemupath']}
        if len(self.topology['conf']) == 0:
            self.topology['conf'].append(tmp_conf)
        else:
            self.topology['conf'][self.hv_id].update(tmp_conf)