OF-1008: Do not send error messages to non-available local users

When the local user that is sent a message delivery failure report is
not online, drop the stanza. This prevents loops where the failure
to deliver the failure message triggers another failure message.

src/java/org/jivesoftware/openfire/MessageRouter.java

@@ -252,7 +252,7 @@ public class MessageRouter extends BasicModule {
         final Message msg = (Message) packet;
 
         if ( msg.getType().equals( Message.Type.chat ) && serverName.equals( recipient.getDomain() ) && recipient.getResource() != null
-                && userManager.isRegisteredUser( recipient.getNode() ) )
+                && routingTable.hasClientRoute( recipient.asBareJID() ) )
         {
             // If message was sent to an unavailable full JID of a user then retry using the bare JID.
             routingTable.routePacket( recipient.asBareJID(), packet, false );