code: protected boolean renameClientObject (Name oldname, Name newname)
      {
          ClientObject clobj = _objmap.remove(oldname);
          if (clobj == null) {
              log.warning("Requested to rename unmapped client object", "username", oldname,
                          new Exception());
              return false;
          }
          _objmap.put(newname, clobj);
          return true;
      }
docs: Renames a currently connected client from <code>oldname</code> to <code>newname</code>.
  
  @return true if the client was found and renamed.