[master] 68ce690c9 The default filter list must not take resp_len into account

[Nils Goroll]

commit 68ce690c990211c967c944aa3bf3b7a85b142a2e
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Sat Apr 4 18:49:00 2020 +0200

    The default filter list must not take resp_len into account
    
    We do not know if we are going to send a body when we construct the
    filter list. It is up to the vdps to handle a null response
    
    Ref #3002

diff --git a/bin/varnishd/cache/cache_vrt_filter.c b/bin/varnishd/cache/cache_vrt_filter.c
index 2bbdcf862..06ae0f6bc 100644
--- a/bin/varnishd/cache/cache_vrt_filter.c
+++ b/bin/varnishd/cache/cache_vrt_filter.c
@@ -346,7 +346,7 @@ resp_default_filter_list(void *arg, struct vsb *vsb)
 
 	CAST_OBJ_NOTNULL(req, arg, REQ_MAGIC);
 
-	if (!req->disable_esi && req->resp_len != 0 &&
+	if (!req->disable_esi &&
 	    ObjHasAttr(req->wrk, req->objcore, OA_ESIDATA))
 		VSB_cat(vsb, " esi");