[#83036806] Refactor ActionMailerQueue::Store.records_for_processing

https://www.pivotaltracker.com/story/show/83036806

* Make the `ActionMailerQueue::Store.records_for_processing` Rails 4
  compatible by extracting the `options` from `.all` to their own
  methods.
Merge pull request #1 from notonthehighstreet/rails4

[#83036806] Refactor ActionMailerQueue::Store.records_for_processing