The dummy image will be created with 1Mib size.
during the snapshot transfer operation the 1Mib
will be transferred even if the dummy image doesnot
contains any data. adding the new image features
`fast-diff,layering,obj-map,exclusive-lock`on the
dummy image will ensure that only the diff is
transferred to the remote cluster.
Signed-off-by: Madhu Rajanna <madhupr007@gmail.com>