the nested call combined with the long parameter list is not very nice to
format/read, let's split it..
Signed-off-by: Fabian Grünbichler <f.gruenbichler@proxmox.com>
for base images we call the volume_import of the parent plugin and pass
it as vm-image instead of base-image, then convert it back as base-image
Signed-off-by: Hannes Duerr <h.duerr@proxmox.com>