Remove unusual explicit calls to policy capability descriptions from Diviner
Summary: Fixes T12015. This is weird and probably got copy/pasted from something else that was also being weird, since the methods were empty and I previously removed them.
Test Plan: Edited a book in Diviner.
Reviewers: chad, avivey
Reviewed By: avivey
Maniphest Tasks: T12015
Differential Revision: https://secure.phabricator.com/D17056