fix differential style break if you cancel inline comment before posting

Summary: see title. Thanks for the report @poop

Test Plan: loaded up FF, left a comment but did not submit and instead cancelled - observed sane UI

Reviewers: epriestley, vrana, poop

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T2460

Differential Revision: https://secure.phabricator.com/D4728

src/applications/differential/view/DifferentialChangesetListView.php

@@ -227,7 +227,7 @@ final class DifferentialChangesetListView extends AphrontView {
     $template =
       '<table><tr>'.
       '<th></th><td>%s</td>'.
-      '<th></th><td colspan="2">%s</td>'.
+      '<th></th><td colspan="3">%s</td>'.
       '</tr></table>';
 
     return array(