php: Workaround for PHP 5.3.3 bug

References:
https://bugs.php.net/bug.php?id=43200
http://stackoverflow.com/a/22521203

include/class.client.php

@@ -433,7 +433,5 @@ class ClientAccount extends UserAccount {
 
 // Used by the email system
 interface EmailContact {
-    function getId();
-    function getEmail();
 }
 ?>