Bug: S3FileSigner does not respect core-site.xml

[Benno49]

Configuring aws endpoint or credentials in core-site.xml does not effect S3FileSigner.
Line 57 CloudFileSighner.scala:

  private val s3Client = ReflectionUtils.newInstance(classOf[DefaultS3ClientFactory], conf)
    .createS3Client(name, new S3ClientCreationParameters())

Parameters get initialized (new S3ClientCreationParameters()) but never configured. Compare to bindAWSClient in S3AFileSystem.java:

parameters = new S3ClientFactory.S3ClientCreationParameters()
        .withCredentialSet(credentials)
        .withEndpoint(endpoint)
        .withMetrics(statisticsContext.newStatisticsFromAwsSdk())
        .withPathStyleAccess(conf.getBoolean(PATH_STYLE_ACCESS, false))
        .withUserAgentSuffix(uaSuffix)
        .withRequestHandlers(auditManager.createRequestHandlers());

    s3 = ReflectionUtils.newInstance(s3ClientFactoryClass, conf)
        .createS3Client(getUri(),
            parameters);

I am not sure why the s3 client of the FileSystem is not used here anyway:

    fs match {
      case _: S3AFileSystem =>
        new S3FileSigner(dataPath, conf, preSignedUrlTimeoutSeconds)