Moved to AWS SDK 1.7.2. With 1.7.2 TransferManager.shutdownNow(boolean) method is introduced
so that when we shutdown the TransferManager after a multipart upload is completed,
the underlying S3 client is closed based on the given boolean value.
Merge branch 's3_multipart_upload' of https://github.com/nezihyigitbasi/presto into s3_multipart_upload