message: Remove redundant room_id
diff: @@ -140,12 +140,10 @@ class RoomViewStore extends Store {
  MatrixClientPeg.get().joinRoom(this._state.roomId, payload.opts).done(() => {
  dis.dispatch({
  action: 'joined_room',
  - room_id: this._state.roomId,
  });
  }, (err) => {
  dis.dispatch({
  action: 'join_room_error',
  - room_id: this._state.roomId,
  err: err,
  });
  const msg = err.message ? err.message : JSON.stringify(err);
  