fog/fog — pull request #1107 by zacharydanger (2012-08-20 15:51:05+00:00)
Title: Update public_url to handle new header casings from Rackspace

For some reason here in the past week or so Rackspace decided to start returning the `X-CDN-URI` headers as `X-Cdn-Uri`, which causes the `public_url` methods to return `nil`.

This patch fixes that, but I'm worried they'll arbitrarily switch back at some point or do something equally as inane.