Fix Versions page

Summary:
- ipull there is wrong
- The `+` wasn't doing what I thought it was doing.
- I already forgot what that detour was doing, so I wrote it down.

Test Plan: Load Versions page, see no error log.

Reviewers: #blessed_reviewers, epriestley

Reviewed By: #blessed_reviewers, epriestley

Subscribers: epriestley

Differential Revision: https://secure.phabricator.com/D14686

src/applications/config/module/PhabricatorConfigVersionsModule.php

@@ -45,9 +45,9 @@ final class PhabricatorConfigVersionsModule
     );
 
     $all_libraries = PhutilBootloader::getInstance()->getAllLibraries();
-    $other_libraries = array_diff($all_libraries, ipull($specs, 'lib'));
-    $specs = $specs + $other_libraries;
-
+    // This puts the core libraries at the top:
+    $other_libraries = array_diff($all_libraries, $specs);
+    $specs = array_merge($specs, $other_libraries);
 
     $futures = array();
     foreach ($specs as $lib) {