Fix Phame Post creation time
Summary: I spent way to long to arrive at this solution. Ref T9360
Test Plan: Publish a new post, see time, unpublish post, see draft. Start a new post, wait 10 minutes, publish, see "now".
Reviewed By: epriestley
Maniphest Tasks: T9360
Differential Revision: https://secure.phabricator.com/D14656