Bugfix/AWS_S3_timeout

1. Traced the problem to this possible issue. https://github.com/aws/aws-sdk-ruby/issues/241
2. It seems that 2.0.0-p353 and AWS sdk 1.33.0 is still having the problem intermittently and others reported to solve the issue with `AWS.config.http_handler.pool.empty!`
3. Make sense to try?