Fix error on paste create via conduit
Summary: default policy to most liberal policy available for the installation
Test Plan: echo "sup man?" | arc paste Was able to view resultant paste with no errors!
Reviewers: epriestley, vrana
Reviewed By: epriestley
CC: aran, Korvin
Maniphest Tasks: T1815
Differential Revision: https://secure.phabricator.com/D3548