psu-stewardship/hydra-ezid — pull request #15 by jeremyf (2013-09-25 17:32:19+00:00)
Title: Moving exceptions to singular file

Given that exceptions have a hierarchy in Ruby
Then we should organize the exceptions to expose any potential
hierarchy.

http://blog.nicksieger.com/articles/2006/09/06/rubys-exception-hierarchy/