Stop running "20150503.repositorysymbols.2.php"

Fixes T8691.

resources/sql/autopatches/20150503.repositorysymbols.2.php

@@ -1,29 +1,6 @@
 <?php
 
-$table = new PhabricatorRepositorySymbol();
-$conn_w = $table->establishConnection('w');
-
-$projects = queryfx_all(
-  $conn_w,
-  'SELECT * FROM %T',
-  'repository_arcanistproject');
-
-foreach ($projects as $project) {
-  $repo = id(new PhabricatorRepositoryQuery())
-    ->setViewer(PhabricatorUser::getOmnipotentUser())
-    ->withIDs(array($project['repositoryID']))
-    ->executeOne();
-
-  if (!$repo) {
-    continue;
-  }
-
-  echo pht("Migrating symbols for '%s' project...\n", $project['name']);
-
-  queryfx(
-    $conn_w,
-    'UPDATE %T SET repositoryPHID = %s WHERE arcanistProjectID = %d',
-    $table->getTableName(),
-    $repo->getPHID(),
-    $project['id']);
-}
+// NOTE: This migration moved existing symbols from Arcanist Projects to
+// Repositories. It stopped running cleanly about two months later, after
+// Spaces were introduced. Since this data is not important and can be
+// trivially regenerated, just stop running the migration. See T8691.