add support for asia-pacific region

[sinhaashish]

fixes #1652

Run the below code

	s3Client, err := minio.New("s3.amazonaws.com", &minio.Options{
		Creds:  credentials.NewStaticV4(<<Access KEy >>, <<Secret Key>>, ""),
		Secure: true,
	})
	if err != nil {
		log.Fatalln(err)
	}

	s3Client.TraceOn(os.Stderr)

	// Make a new bucket.
	err = s3Client.MakeBucket(context.Background(), "hellominio", minio.MakeBucketOptions{Region: "ap-southeast-3"})

	if err != nil {
		log.Fatalln(err)
	}

[vadmeste]

LGTM