message: [clippy] fix logger clippy check.
diff: @@ -143,10 +143,10 @@ fn build_config(arg: LoggerConfigArg) -> Result<Config> {
  }
  fn env_log_level(default_level: &str) -> LevelFilter {
  - let level = std::env::var("RUST_LOG").unwrap_or(default_level.to_string());
  + let level = std::env::var("RUST_LOG").unwrap_or_else(|_| default_level.to_string());
  level
  .parse()
  - .expect(format!("Unexpect log level: {}", level).as_str())
  + .unwrap_or_else(|_| panic!("Unexpect log level: {}", level))
  }
  lazy_static! {
  @@ -164,7 +164,7 @@ pub fn init_with_default_level(default_level: &str) -> Arc<LoggerHandle> {
  build_config(LoggerConfigArg::new(true, level, None)).expect("build log config fail.");
  let handle = match log4rs::init_config(config) {
  Ok(handle) => handle,
  - Err(e) => panic!(format!("{}", e.to_string())),
  + Err(e) => panic!(e.to_string()),
  };
  let logger_handle = LoggerHandle::new(true, level, None, handle);
  