message: Remove incorrect default config for poll open, add TODO.
diff: @@ -92,11 +92,7 @@ impl PoolCommandExecutor {
  }
  fn open(&self, name: &str, config: Option<&str>, cb: Box<Fn(Result<i32, PoolError>) + Send>) {
  - let config: String = match config {
  - Some(s) => String::from(s),
  - None => format!("{{\"genesis_txn\": \"{}.txn\"}}", name),
  - };
  - match self.pool_service.open(name, config.as_str()) {
  + match self.pool_service.open(name, config.unwrap_or("TODO: default config")) { //TODO
  Err(err) => { cb(Err(err)); }
  Ok(id) => { self.pending_cbs_opening.borrow_mut().insert(id, cb); }
  };
  