导出VPS时，中断操作后，启动VPS，出现以下错误：
Error: Starting VM 'Windows 2003' on 'XenServer' - Internal error: Failure("The VDI cf786ea2-1364-4ff4-b4c4-839aa1cf3414 is already attached in RO mode; it can't be attached in RW mode!")重启xapi即可解决：
xe-toolstack-restart
