Utils_Crypt: Fix PHP start tag.

Avoid using the short tag style, since it may be disabled. Thanks to
Thijs Kinkhorst for identifying this bug.

git-svn-id: https://simplesamlphp.googlecode.com/svn/trunk@2973 44740490-163a-0410-bde0-09ae8108e29a

lib/SimpleSAML/Utils/Crypto.php

-<?
+<?php
+
 /**
  * A class for crypto related functions
  *