@Override
    public void stop() {
        super.stop();
        infoHandler.removeServerNodeInfoProvider(NAMESPACE);
        itemsHandler.removeServerNodeInfoProvider(NAMESPACE);
    }
Implements JEP-0013: Flexible Offline Message Retrieval. Allows users to request number of
messages, request message headers, retrieve specific messages, remove specific messages,
retrieve all messages and remove all messages.

@author Gaston Dombiak
xmppserver/src/main/java/org/jivesoftware/openfire/handler/IQOfflineMessagesHandler.java