Make clear that .host_header is a fallback value
Make clear that .host_header is a fallback value

gquintard/Varnish-Cache,feld/Varnish-Cache,feld/Varnish-Cache,feld/Varnish-Cache,gquintard/Varnish-Cache,feld/Varnish-Cache,feld/Varnish-Cache,gquintard/Varnish-Cache,gquintard/Varnish-Cache