boto/boto — pull request #1152 by mikek (2012-12-01 18:24:12+00:00)
Title: S3Connection.build_post_form_args(): omit 'content-length-range' from fields list

It appears that `content-length-range` is not a part of [POST form fields spec] (http://docs.amazonwebservices.com/AmazonS3/latest/API/RESTObjectPOST.html), and S3 actually complains if it is present in request. Putting it to `conditions` is enough.