Attribute revision promotion from "Draft" to "Needs Review" to the author

Summary:
Ref T2543. When Harbormaster finishes builds and promotes a draft revision to review, we currently publish "Harbormaster requested review of...".

Instead, attribute this action to the author, since that's more natural and more useful.

Test Plan: Promoted a diff locally, saw it attributed to me rather than Harbormaster.

Reviewers: amckinley

Reviewed By: amckinley

Maniphest Tasks: T2543

Differential Revision: https://secure.phabricator.com/D18730

src/applications/differential/editor/DifferentialTransactionEditor.php

@@ -1537,7 +1537,13 @@ final class DifferentialTransactionEditor
     if ($object->isDraft() && $auto_undraft) {
       $active_builds = $this->hasActiveBuilds($object);
       if (!$active_builds) {
+        // When Harbormaster moves a revision out of the draft state, we
+        // attribute the action to the revision author since this is more
+        // natural and more useful.
+        $author_phid = $object->getAuthorPHID();
+
         $xaction = $object->getApplicationTransactionTemplate()
+          ->setAuthorPHID($author_phid)
           ->setTransactionType(
             DifferentialRevisionRequestReviewTransaction::TRANSACTIONTYPE)
           ->setOldValue(false)