FOR UPDATE doesn't work if it's not added after limit

[dakorpar]

Version: 4.2.0

Bug Description

forUpdate doesn't work correct with fluent interface when after it we're calling fetch or fetchSingle. FOR UPDATE is added before limit and we get Sql exception

Steps To Reproduce

	$db->select('whatever')->from('table)
		->where('id = %i', $id)
		->forUpdate()
		->fetchSingle();

however this works:

	$db->select('whatever')->from('table)
		->where('id = %i', $id)
		->limit(1)
		->forUpdate()
		->fetchSingle();

[dg]

This would require change the limit() behavior in the Fluent, which would cause a BC break, so I don't want to deal with it at all…