fog/fog — pull request #1137 by fcheung (2012-09-09 13:43:29+00:00)
Title: [AWS|Storage] Mark upload_part as idempotent s3

The [upload part](http://docs.amazonwebservices.com/AmazonS3/latest/API/mpUploadUploadPart.html) request is safe to retry - if you repeat it s3 just overwrites the previously received part with the same partNumber. Surely this means we should mark the request as idempotent so that excon will retry for us in case of failures? At the moment it looks like failure on any part would make the whole upload fail and call abort_multipart_upload

I also think we should be setting Content-MD5 to enable s3 to reject invalid parts. I noticed [Fog::Storage.parse_data](https://github.com/fog/fog/blob/master/lib/fog/storage.rb#L81) has some commented out code for calculating this, but I wasn't sure what was up so I just updated the file model to calculate the MD5 for the part