Update to Rails 3.2.13

This version of Rails contains security fixes for the following
vulnerabilities:

* [CVE-2013-1854] Symbol DoS vulnerability in Active Record
* [CVE-2013-1855] XSS vulnerability in sanitize_css in Action Pack
* [CVE-2013-1856] XML Parsing Vulnerability affecting JRuby users
* [CVE-2013-1857] XSS Vulnerability in the sanitize helper of Rails
Silence `:rubygems` Bundler deprecation notice.

Message from Bundler before this change:

The source :rubygems is deprecated because HTTP requests are insecure.

Please change your source to 'https://rubygems.org' if possible, or
'http://rubygems.org' if not.
Merge branch 'CHEF-4059'