CA-41230: In VM.{snapshot,clone}, keep track of whether a new VDI has actually been created and therefore, whether that VDI should be deleted on failure. In particular CDs are shared not duplicated and so the cleanup code shouldn't try to delete them.
CA-41230: In VM.{snapshot,clone}, keep track of whether a new VDI has actually been created and therefore, whether that VDI should be deleted on failure. In particular CDs are shared not duplicated and so the cleanup code shouldn't try to delete them.

Unfortunately the 'writable ISO SR' support changes the default NFS ISO SR mount options to read/write from read/only, exposing this bug.

Signed-off-by: David Scott <63c9eb0ea83039690fefa11afe17873ba8278a56@eu.citrix.com>

koushikcgit/xcp-rrdd,koushikcgit/xcp-networkd,koushikcgit/xcp-rrdd,johnelse/xcp-rrdd,simonjbeaumont/xcp-rrdd,sharady/xcp-networkd,simonjbeaumont/xcp-rrdd,johnelse/xcp-rrdd,robhoes/squeezed,koushikcgit/xcp-rrdd,djs55/xcp-rrdd,djs55/squeezed,djs55/xcp-networkd,djs55/xcp-networkd,djs55/xcp-rrdd,koushikcgit/xcp-networkd,sharady/xcp-networkd