helpsite url can't be localised at install time

Localised distributions can use the localise.xml file to force a default helpsite for new installs. This has been broken since 1.6.

To test: patch and add this url in localise.xml

<?xml version="1.0" encoding="utf-8"?>
<localise version="3.2" client="installation" >
	<forceLang></forceLang>
	<helpurl>http://help.joomla.fr/3/index.php?option=com_help&amp;keyref=Help{major}{minor}:{keyref}</helpurl>
	<debug>0</debug>
	<sampledata></sampledata>
	<params/>
</localise>

If none set the joomla.org en-GB one will be used