message: Fix deprecation warning on newer versions of `failure`.
diff: @@ -14,8 +14,8 @@ pub struct AccessError {
  pub type Result<T> = ::std::result::Result<T, Error>;
  pub(crate) fn log_error(e: &Error) {
  - error!("error: {}", e.cause());
  - for cause in e.causes() {
  + error!("error: {}", e.as_fail());
  + for cause in e.iter_chain() {
  error!("caused by: {}", cause);
  }
  