void childNodeModified(Node child, Message notification){
        // Broadcast event notification to subscribers
        broadcastCollectionNodeEvent(child, notification);
    }
Notification that a child node configuration was modified. Trigger notifications
to node subscribers whose subscription type is {@link NodeSubscription.Type#nodes} and
have the proper depth.

@param child the deleted node that was removed from this node.
@param notification message which will be sent to subscribers.
xmppserver/src/main/java/org/jivesoftware/openfire/pubsub/CollectionNode.java