Convert virtual disk

• PCVD_CANCEL : cancel disk conversion
• PCVD_TO_PLAIN_DISK : convert disk from expanding to plain disk
• PCVD_TO_EXPANDING_DISK : convert disk from plain to expanding disk
• PCVD_TO_SPLIT_DISK : convert disk from non-split to split disk
• PCVD_TO_NON_SPLIT_DISK : convert disk from split to non-split disk
• PCVD_MERGE_ALL_SNAPSHOTS : merge all disk snapshots

enum _PRL_CONVERT_VIRTUAL_DISK {
  PCVD_CANCEL = 1<<(PACF_MAX+1),
  PCVD_TO_PLAIN_DISK = 1<<(PACF_MAX+2),
  PCVD_TO_EXPANDING_DISK = 1<<(PACF_MAX+3),
  PCVD_TO_SPLIT_DISK = 1<<(PACF_MAX+4),
  PCVD_TO_NON_SPLIT_DISK = 1<<(PACF_MAX+5),
  PCVD_MERGE_ALL_SNAPSHOTS = 1<<(PACF_MAX+6)
};