Fix an issue with "Auditors:" where an edge edit was used as a PHID list

Summary:
See <https://discourse.phabricator-community.org/t/runtimeexception-during-import-of-commit/3801>. When importing commits with "Auditors:", a raw transaction new value (with an edge edit map using a "+" key) may be passed as an unmentionable PHID list.

Instead, pass an actual PHID list.

Test Plan:
  - Pushed a commit with "Auditors: duck".
  - Ran daemons.
    - Before patch: umentionable PHID exception.
    - After patch: clean commit import.
  - Verified "duck" was added as an auditor.

Differential Revision: https://secure.phabricator.com/D21181

src/applications/audit/editor/PhabricatorAuditEditor.php

@@ -232,14 +232,22 @@ final class PhabricatorAuditEditor
     PhabricatorLiskDAO $object,
     PhabricatorApplicationTransaction $xaction) {
 
+    $auditors_type = DiffusionCommitAuditorsTransaction::TRANSACTIONTYPE;
+
     $xactions = parent::expandTransaction($object, $xaction);
+
     switch ($xaction->getTransactionType()) {
       case PhabricatorAuditTransaction::TYPE_COMMIT:
-        $request = $this->createAuditRequestTransactionFromCommitMessage(
+        $phids = $this->getAuditRequestTransactionPHIDsFromCommitMessage(
           $object);
-        if ($request) {
-          $xactions[] = $request;
-          $this->addUnmentionablePHIDs($request->getNewValue());
+        if ($phids) {
+          $xactions[] = $object->getApplicationTransactionTemplate()
+            ->setTransactionType($auditors_type)
+            ->setNewValue(
+              array(
+                '+' => array_fuse($phids),
+              ));
+          $this->addUnmentionablePHIDs($phids);
         }
         break;
       default:
@@ -268,7 +276,7 @@ final class PhabricatorAuditEditor
     return $xactions;
   }
 
-  private function createAuditRequestTransactionFromCommitMessage(
+  private function getAuditRequestTransactionPHIDsFromCommitMessage(
     PhabricatorRepositoryCommit $commit) {
 
     $actor = $this->getActor();
@@ -297,12 +305,7 @@ final class PhabricatorAuditEditor
       return array();
     }
 
-    return $commit->getApplicationTransactionTemplate()
-      ->setTransactionType(DiffusionCommitAuditorsTransaction::TRANSACTIONTYPE)
-      ->setNewValue(
-        array(
-          '+' => array_fuse($phids),
-        ));
+    return $phids;
   }
 
   protected function sortTransactions(array $xactions) {