'Query pool info when Dsware is single-pool version.'

def _update_single_pool_info_status(self):

    status = {}
    status['volume_backend_name'] = self.configuration.volume_backend_name
    status['vendor_name'] = 'Open    Source'
    status['driver_version'] = self.VERSION
    status['storage_protocol'] = 'dsware'
    status['total_capacity_gb'] = 0
    status['free_capacity_gb'] = 0
    status['reserved_percentage'] = self.configuration.reserved_percentage
    status['QoS_support'] = False
    pool_id = 0
    pool_info = self.dsware_client.query_pool_info(pool_id)
    result = pool_info['result']
    if (result == 0):
        status['total_capacity_gb'] = (float(pool_info['total_capacity']) / 1024)
        status['free_capacity_gb'] = ((float(pool_info['total_capacity']) - float(pool_info['used_capacity'])) / 1024)
        LOG.debug('total_capacity_gb    is    %s,    free_capacity_gb    is    %s.', status['total_capacity_gb'], status['free_capacity_gb'])
        self._stats = status
    else:
        self._stats = None
