This commit enables libvirt users to use layered encryption
of RBD images, using the librbd encryption engine.
This allows opening of an encrypted cloned image
whose parent is encrypted with a possibly different encryption key.
To open such images, multiple encryption secrets are expected
to be defined under the encryption XML tag.
Signed-off-by: Or Ozeri <oro@il.ibm.com>
Reviewed-by: Peter Krempa <pkrempa@redhat.com>
