Orphan list bug

PT story: https://www.pivotaltracker.com/story/show/79488584

- Fixed all three bugs
- Introduced features to test the fix
- Introduced specs to ensure an orphan list can only be created for an active partner
- Introduced orphan_list factory
I understand the rationale here, but this test is identical to `it 'should have a valid factory'`. What about merging them into `it 'should have a valid factory and belong to an active partner'`