Don't treat links to redyoutube.com as YouTube

Test Plan: `http://redyoutube.com/?v=1`

Reviewers: tuomaspelkonen, epriestley

Reviewed By: epriestley

CC: aran, epriestley

Differential Revision: https://secure.phabricator.com/D2842

src/infrastructure/markup/remarkup/markuprule/PhabricatorRemarkupRuleYoutube.php

@@ -26,7 +26,7 @@ final class PhabricatorRemarkupRuleYoutube
     $this->uri = new PhutilURI($text);
 
     if ($this->uri->getDomain() &&
-        preg_match('/youtube\.com$/', $this->uri->getDomain())) {
+        preg_match('/(^|\.)youtube\.com$/', $this->uri->getDomain())) {
       return $this->markupYoutubeLink();
     }