do not expose version in outgoing mails FS#2701

inc/Mailer.class.php

@@ -51,7 +51,7 @@ class Mailer {
         $this->allowhtml = (bool)$conf['htmlmail'];
 
         // add some default headers for mailfiltering FS#2247
-        $this->setHeader('X-Mailer', 'DokuWiki '.getVersion());
+        $this->setHeader('X-Mailer', 'DokuWiki');
         $this->setHeader('X-DokuWiki-User', $_SERVER['REMOTE_USER']);
         $this->setHeader('X-DokuWiki-Title', $conf['title']);
         $this->setHeader('X-DokuWiki-Server', $server);