R1:767397ee14ec

Reject objects with invalid policies instead of fataling

Summary: This is correct, but the root cause of the issue isn't very clear to me.

Test Plan: Poked around various pages which filter objects.

Reviewers: joshuaspence

Reviewed By: joshuaspence

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D11727