When I "PUT" an object using a pre-signed by localstack S3 URL, the localstack responds with "Content Length: 233" and `<PutObjectResponse>...</PutObjectResponse>` XML in the body. 

When I run the same code against AWS S3, the content length is 0 and response body blank. Would be great if localstack matched the AWS S3 response.

Running the latest 0.9.3 localstack docker image.
bucket = 'test-bucket'
        s3_client = aws_stack.connect_to_service('s3')
        s3_client.create_bucket(Bucket=bucket)
        s3_client.put_bucket_cors(
            Bucket=bucket,
            CORSConfiguration={
                'CORSRules': [{'AllowedMethods': ['GET', 'POST', 'PUT', 'DELETE'],
                               'AllowedOrigins': ['localhost']}]
            }
        )
        response = s3_client.get_bucket_cors(Bucket=bucket)
        self.assertEqual(response['ResponseMetadata']['HTTPStatusCode'], 200)
        
        s3_client.delete_bucket(Bucket=bucket)
    def test_s3_get_response_headers(self):