Phriction - fix "unknown policy" on document create

Summary: when creating new documents the policy object wasn't being initialized properly. update the code to use the new handy initializeNewDocument method. Fixes T6527.

Test Plan: viewed a doc at /w/asdsadsadsdas/ and saw the correct policy setting

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Maniphest Tasks: T6527

Differential Revision: https://secure.phabricator.com/D10837