In many places we were checking for identity which was the shorthand for
checking if the resource had been saved by the service.
The #persisted? method was added to show a clearer intent and also offer
minimal ActiveModel interface
This patch adds support for mocking the cloudfront API.
CDN Tests now can both be run with mocking and non mocking
activated.
Signed-off-by: Brice Figureau <brice-puppet@daysofwonder.com>
