Summary:
Conduit doesn't currently have an analog to "shouldAllowPublic", so the recent policy checks added here caught legitimate Conduit calls when viewing Diffusion as a logged-out user.
Add `shouldAllowPublic()` and set it for all the Diffusion queries.
(More calls probably need this, but we can add it when we hit them.)
Test Plan: Looked at Diffusion as a logged-out user with public access enabled.
Reviewers: btrahan
Reviewed By: btrahan
CC: aran
Differential Revision: https://secure.phabricator.com/D7380
90b83d7a92