AFNetworking/AFNetworking — pull request #165 by mgp (2012-01-07 05:26:55+00:00)
Title: "Content-disposition" should be "form-data" for a single file.

The `Content-disposition` should only be `file` if one of multiple files in a subpart. See the end of http://www.w3.org/TR/html4/interact/forms.html, section 17.13.4, for details.
Without this patch, we experienced Tornado failing to accept a file upload.