remove unused method, re #957

lib/classes/SkipLinks.php

@@ -101,20 +101,4 @@ class SkipLinks
         }
         return $GLOBALS['template_factory']->render('skiplinks', compact('navigation'));
     }
-
-    /**
-     * Checks if there is another link at the same position and if it is overwritable.
-     *
-     * @return boolean true if the link at the same position is overwritable
-     */
-    private static function checkOverwrite($link)
-    {
-        if (isset(self::$position[$link['position']])) {
-            return false;
-        }
-        if (empty($link['overwrite'])) {
-            self::$position[$link['position']] = true;
-        }
-        return true;
-    }
 }