Introduced in v3.0.0-rc1~336, the commit message doesn't really
justifies the expensive domain def copy creation. Now, that
vm->def is guarded in this function by job acquirement we can use
vm->def directly.
Signed-off-by: NMichal Privoznik <mprivozn@redhat.com>
Reviewed-by: NJán Tomko <jtomko@redhat.com>