Diffusion - fix commits not importing fully

Summary: Fixes T6336. Turns out that the function to update the import status updates that database and doesn't update the object. If the object doesn't get the pertinent update AND there's a herald rule that runs, then the object is later re-saved without ever getting the update flag.

Test Plan: logic in the ole sandbox and going to push it to prod and run re-parse on impacted commits

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley, chad

Maniphest Tasks: T6336

Differential Revision: https://secure.phabricator.com/D10723