Ticket #10140: update-core.diff

wp-admin/includes/update-core.php

@@ -229 +229 @@
         $result = copy_dir($from . '/wordpress', $to);
         if ( is_wp_error($result) ) {
                 $wp_filesystem->delete($maintenance_file);
-                $wp_filesystem->delete($working_dir, true);
+                $wp_filesystem->delete($from, true);
                 return $result;
         }