message: db.file: allow overriding the region
  This is useful when testing against play.minio.io, as it requires the
  us-east-1 region name.
diff: @@ -133,7 +133,8 @@ fn s3_client() -> Option<S3Client> {
  rusoto_core::request::HttpClient::new().unwrap(),
  creds,
  std::env::var("S3_ENDPOINT").ok().map(|e| Region::Custom {
  - name: "us-west-1".to_owned(),
  + name: std::env::var("S3_REGION")
  + .unwrap_or_else(|| "us-west-1".to_owned()),
  endpoint: e,
  }).unwrap_or(Region::UsWest1),
  ))
  