s3cmd: --devel update to 1.5.0-beta1

Upstream ChangeLog (update from alpha3 -> beta1):
```
s3cmd 1.5.0-beta1    -   2013-12-02
=================
* Brougt to you by Matt Domsch and contributors, thanks guys! :)
* Multipart upload improvements (Eugene Brevdo, UENISHI Kota)
* Allow --acl-grant on AWS groups (Dale Lovelace)
* Added Server-Side Encryption support (Kevin Daub)
* Improved MIME types detections and content encoding (radomir,
  Eric Drechsel, George Melika)
* Various smaller changes and bugfixes from many contributors

s3cmd 1.5.0-alpha3   -   2013-03-11
==================
* Persistent HTTP/HTTPS connections for massive speedup (Michal Ludvig)
* New switch --quiet for suppressing all output (Siddarth Prakash)
* Honour "umask" on file downloads (Jason Dalton)
* Various bugfixes from many contributors
```