fabpot/Silex — pull request #769 by igorw (2013-08-25 14:59:13+00:00)
Title: Only convert attributes on the request that actually exist

Fixes #768.

Note: This could be considered a BC break, since it on longer implicitly creates attributes on the request. I'd consider it quite a minor break. The name `convert` implies that the attribute must be present, and I personally would consider this a bug fix instead.