Fix an issue with Diffusion where paging by commit date would fail

Summary: When loading the cursor repository, we need to load the most recent
commit too if we're paging by commit date. This fixes a fatal for installs
with more than 100 repositories.

Auditors: btrahan

src/applications/repository/query/PhabricatorRepositoryQuery.php

@@ -163,10 +163,15 @@ final class PhabricatorRepositoryQuery
   }
 
   private function loadCursorObject($id) {
-    $results = id(new PhabricatorRepositoryQuery())
+    $query = id(new PhabricatorRepositoryQuery())
       ->setViewer($this->getPagingViewer())
-      ->withIDs(array((int)$id))
-      ->execute();
+      ->withIDs(array((int)$id));
+
+    if ($this->order == self::ORDER_COMMITTED) {
+      $query->needMostRecentCommits(true);
+    }
+
+    $results = $query->execute();
     return head($results);
   }