Previously, a registered restorable property would only be
unregistered if the property was animated (see
QStateMachinePrivate::_q_animationFinished()).
But if a property is set directly, it should also be unregistered;
otherwise, the state machine would use the previously saved (stale)
value the next time that property should be restored.
Change-Id: I5d246aa5355ddd0ba5f81b0186a9f0e4f3bbaa3f
Reviewed-by: Eskil Abrahamsen Blomfeldt <eskil.abrahamsen-blomfeldt@nokia.com>