Write a "resign" audit relationship even if actor has no relationship

Summary: Ref T4896. I got this logic slightly wrong when porting it over: we always want to write this relationship, to allow members of a project with an audit request against a commit to resign and get it out of their queue.

Test Plan:
  - Resigned from a commit with an existing relationship.
  - Resigned from a commit with no existing relationship, saw one added.

Reviewers: btrahan, joshuaspence, mbishopim3

Reviewed By: mbishopim3

Subscribers: epriestley

Maniphest Tasks: T4896

Differential Revision: https://secure.phabricator.com/D10137

src/applications/audit/editor/PhabricatorAuditEditor.php

@@ -161,11 +161,23 @@ final class PhabricatorAuditEditor
               $requests = mpull($requests, null, 'getAuditorPHID');
               $actor_request = idx($requests, $actor_phid);
 
-              if ($actor_request) {
+              // If the actor doesn't currently have a relationship to the
+              // commit, add one explicitly. For example, this allows members
+              // of a project to resign from a commit and have it drop out of
+              // their queue.
+
+              if (!$actor_request) {
+                $actor_request = id(new PhabricatorRepositoryAuditRequest())
+                  ->setCommitPHID($object->getPHID())
+                  ->setAuditorPHID($actor_phid);
+
+                $requests[] = $actor_request;
+                $object->attachAudits($requests);
+              }
+
               $actor_request
                 ->setAuditStatus($status_resigned)
                 ->save();
-              }
               break;
             case PhabricatorAuditActionConstants::ACCEPT:
             case PhabricatorAuditActionConstants::CONCERN: