Fix diffusion.looksoon call to actually work

Summary:
This is all derped up, and we ignore the error so old installs don't break.

Underp it.

Test Plan: Did arc land, verified that the call actually went through successfully.

Reviewers: btrahan, davedash

Reviewed By: davedash

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D9271