Fix audit commenting where there are only inlines

Summary: been some changes here and this code was broked. turns out we re-assign $action like two lines later and never used the initial value, so we can simply delete the offending line. Fixes T5745.

Test Plan: submitted inline comment pre-patch and fatal. re-submitted post patch and great success!

Reviewers: epriestley

Reviewed By: epriestley

Subscribers: epriestley, Korvin

Maniphest Tasks: T5745

Differential Revision: https://secure.phabricator.com/D10078