BUG-ID: CLOUDSTACK-7102. Volume migration fails with 'VM i-2-3-VM does not exist in VMware datacenter' expection.
Look for a VM in vCenter based on both the vCenter name and CS internal name (required in case 'vm.instancename.flag' is enabled).
During Attach Volume and Volume Migration, for lookup and other operations use VM's name as obtained from vCenter instead of using the name set in the agent command.