kbase: backing_chains: Clarify some aspects of image probing
kbase: backing_chains: Clarify some aspects of image probing

Signed-off-by: Peter Krempa <2cf5c04c61aa466e4a47bfedc747d17279c72ffc@redhat.com>
Reviewed-by: Daniel P. Berrangé <bb938cf255e055ff3507f2627d214e8e62118fcf@redhat.com>

zippy2/libvirt,crobinso/libvirt,fabianfreyer/libvirt,crobinso/libvirt,fabianfreyer/libvirt,olafhering/libvirt,jardasgit/libvirt,olafhering/libvirt,jardasgit/libvirt,olafhering/libvirt,nertpinx/libvirt,jfehlig/libvirt,jfehlig/libvirt,jardasgit/libvirt,libvirt/libvirt,jfehlig/libvirt,fabianfreyer/libvirt,olafhering/libvirt,jfehlig/libvirt,libvirt/libvirt,libvirt/libvirt,nertpinx/libvirt,zippy2/libvirt,jardasgit/libvirt,zippy2/libvirt,nertpinx/libvirt,fabianfreyer/libvirt,zippy2/libvirt,nertpinx/libvirt,crobinso/libvirt,libvirt/libvirt,fabianfreyer/libvirt,nertpinx/libvirt,jardasgit/libvirt,crobinso/libvirt