Fixed incorrect resource in JID.

git-svn-id: http://svn.igniterealtime.org/svn/repos/openfire/trunk@8646 b35dd754-fafc-0310-a699-88a17e54d16e

src/java/org/jivesoftware/openfire/muc/spi/MUCRoomImpl.java

@@ -937,7 +937,7 @@ public class MUCRoomImpl implements MUCRoom {
 
         public JID getRoleAddress() {
             if (crJID == null) {
-                crJID = new JID(room.getName(), server.getServiceDomain(), "", true);
+                crJID = new JID(room.getName(), server.getServiceDomain(), null, true);
             }
             return crJID;
         }