predicate/dag: Node destructor now cleans up childrens parent lists.
predicate/dag: Node destructor now cleans up childrens parent lists.

ironbee/ironbee,b1v1r/ironbee,ironbee/ironbee,b1v1r/ironbee,ironbee/ironbee,ironbee/ironbee,b1v1r/ironbee,ironbee/ironbee,ironbee/ironbee,ironbee/ironbee,b1v1r/ironbee,b1v1r/ironbee,ironbee/ironbee,b1v1r/ironbee,b1v1r/ironbee,b1v1r/ironbee,b1v1r/ironbee,ironbee/ironbee,ironbee/ironbee,b1v1r/ironbee,ironbee/ironbee,b1v1r/ironbee,ironbee/ironbee,b1v1r/ironbee