Cinder-backup progress notification has incorrect percentage.

[Jon Cui]

In the process of volume backup, I found the percentage number was wrong for progress notification.

I added one log inside method "_send_progress_notification" to show that.

def _send_progress_notification(self, context, backup, object_meta,
        total_block_sent_num, total_volume_size):
 backup_percent = total_block_sent_num * 100 / total_volume_size
 object_meta['backup_percent'] = backup_percent
 LOG.warning('++++ backup_percent is %s', backup_percent)
 volume_utils.notify_about_backup_usage(context,
             backup,
             "createprogress",
             extra_usage_info=
             object_meta)

and log records were shown bellow.

2021-03-08 15:02:28.159 870682 WARNING cinder.backup.chunkeddriver [-] ++++ backup_percent is 1.5832483768463135e-05
2021-03-08 15:02:33.165 870682 WARNING cinder.backup.chunkeddriver [-] ++++ backup_percent is 1.5832483768463135e-05