Security: TinyMCE spellchecker security fix for CVE-2012-6112 / 2.11.9

This is TinyMCE spellchecker security fix for CVE-2012-6112 from
https://github.com/tinymce/tinymce_spellchecker_php/commit/22910187bfb9edae90c26e10100d8145b505b974.