before syncing an image we first check if it's already present in our storage
to do that we get the manifest from remote and compare it with the local one
but in the case of syncing docker images, because the conversion to OCI format is done while
syncing, we get a docker manifest before conversion, so sync detects that local manifest and
remote one are different, so it starts syncing again.
to overcome this, convert remote docker manifests to OCI manifests and then compare.
Signed-off-by: Petu Eusebiu <peusebiu@cisco.com>
