Patch to overcome rare cases, when version listing of AWS S3 object lists only 1000 versions

[vlcinsky]

I experienced some versioned objects, which have millions versions, but in some rare cases it listed only 1000 versions. If max_keys parameter is used and set to value 999 or less, then this problem is resolved (at least on the side of the client, it seems to be long living bug in AWS S3).
Patch is shown here: https://gist.github.com/1225558 and is in full detail described in this blog entry: http://ridingpython.blogspot.com/2011/09/resolving-incomplete-aws-s3-version.html