vtest "vcc_feature::err_unref should also cover subs"

server s1 {
	rxreq
	expect req.url == "/bar"
	txresp -body "foobar"
} -start

vinyl v1 -arg "-p vcc_feature=-err_unref" -vcl+backend {
	sub foobar {
		set req.http.foobar = "foobar";
	}
} -start

client c1 {
	txreq  -url /bar
	rxresp
	expect resp.bodylen == 6
} -run
