Added no-cache header
Added no-cache header

This prevents Varnish from caching the captcha image
RicoVZ/CaptchaBundle,max-kovpak/CaptchaBundle,StudioMaX/CaptchaBundle,max-kovpak/CaptchaBundle,RicoVZ/CaptchaBundle,StudioMaX/CaptchaBundle,Gregwar/CaptchaBundle