parallels: commit with PVCF_DETACH_HDD_BUNDLE flag
PCS removes disk image from filesystem, if you remove it
from config. There is a special flag PVCF_DETACH_HDD_BUNDLE
which allow to remove disk only from VM/CT config.
If you call virDomainDefine and remove some disk from
config it should be preserved, so call PrlVm_CommitEx
always with flag PVCF_DETACH_HDD_BUNDLE.