message: qlog/client: Centralize filename generation within qlog_new()
diff: @@ -453,12 +453,8 @@ fn client(
  },
  );
  - let qlog_filename = format!(
  - "{}-{}",
  - hostname,
  - client.conn().path().unwrap().remote_cid()
  - );
  - client.set_qlog(qlog_new(args, &qlog_filename)?);
  + let qlog = qlog_new(args, hostname, client.conn())?;
  + client.set_qlog(qlog);
  let mut h = Handler {
  streams: HashMap::new(),
  @@ -472,10 +468,11 @@ fn client(
  Ok(())
  }
  -fn qlog_new(args: &Args, filename: &str) -> Res<Option<NeqoQlog>> {
  +fn qlog_new(args: &Args, hostname: &str, conn: &Connection) -> Res<Option<NeqoQlog>> {
  if let Some(qlog_dir) = &args.qlog_dir {
  let mut qlog_path = qlog_dir.to_path_buf();
  - qlog_path.push(format!("{}.qlog", filename));
  + let filename = format!("{}-{}.qlog", hostname, conn.path().unwrap().remote_cid());
  + qlog_path.push(filename);
  let f = OpenOptions::new()
  .write(true)
  @@ -905,10 +902,7 @@ mod old {
  client.set_ciphers(&ciphers)?;
  }
  - client.set_qlog(qlog_new(
  - args,
  - &format!("{}-{}", origin, client.path().unwrap().remote_cid()),
  - )?);
  + client.set_qlog(qlog_new(args, origin, &client)?);
  let mut h = HandlerOld {
  streams: HashMap::new(),
  