Fix render :text => false and render :text => nil

Obie Fernandez (Best Online Casino in Australia | Top Licensed Casinos for Gamblers) was asking in the #rails-contrib channel about getting this ticket (http://dev.rubyonrails.org/ticket/6684) fixed. If someone's free could you please review/verify it and appease the "ignored" ticket reporter ;)?

Cheers, Chu Yeow

+1 looks like a smart, easy fix (Disclaimer: I haven't applied the patch myself)