virDomainSnapshotRedefineValidate: Don't modify the snapshot definition
virDomainSnapshotRedefineValidate: Don't modify the snapshot definition

It is not expected that a function with 'Validate' in the name actually
modifies the validated object, even worse when it even modifies another
object and the ultimatively worst bit is that it doesn't undo the mess
if the validation fails midway.

Move the stealing of the domain definition from the definition of a
snapshot being redefined into the caller along with the call to
virDomainSnapshotAlignDisks.

Signed-off-by: Peter Krempa <2cf5c04c61aa466e4a47bfedc747d17279c72ffc@redhat.com>
Reviewed-by: Ján Tomko <4cab11cfb98d3c937327354a78eb07dbb6ee2bc6@redhat.com>

jfehlig/libvirt,olafhering/libvirt,zippy2/libvirt,libvirt/libvirt,crobinso/libvirt,olafhering/libvirt,crobinso/libvirt,libvirt/libvirt,crobinso/libvirt,olafhering/libvirt,zippy2/libvirt,jfehlig/libvirt,jfehlig/libvirt,olafhering/libvirt,jfehlig/libvirt,zippy2/libvirt,libvirt/libvirt,crobinso/libvirt,zippy2/libvirt,libvirt/libvirt