This will be used later on in implementation of new API
virDomainSetLifecycleAction().  In order to use it, we need to store
the value in status XML to not lose the information if libvirtd is
restarted.

If some guest was started by old libvirt where it was not possible
to change the lifecycle action for running guest, we can safely
detect it based on the current actions from the status XML.
Reviewed-by: NJohn Ferlan <jferlan@redhat.com>
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>