[master] e2b43f86f also reset filter_list upon cleanup

[Nils Goroll]

commit e2b43f86fdf719c2f9cf1f6f976e5bef064ea565
Author: Nils Goroll <nils.goroll at uplex.de>
Date:   Wed Oct 2 16:43:09 2019 +0200

    also reset filter_list upon cleanup
    
    in particular because it may live on the workspace.
    
    Required for #3009

diff --git a/bin/varnishd/cache/cache_fetch.c b/bin/varnishd/cache/cache_fetch.c
index ec393a092..130278b65 100644
--- a/bin/varnishd/cache/cache_fetch.c
+++ b/bin/varnishd/cache/cache_fetch.c
@@ -94,6 +94,8 @@ vbf_cleanup(struct busyobj *bo)
 	CHECK_OBJ_NOTNULL(vfc, VFP_CTX_MAGIC);
 
 	VFP_Close(vfc);
+	bo->filter_list = NULL;
+
 	if (bo->director_state != DIR_S_NULL)
 		VDI_Finish(bo);
 }
@@ -253,7 +255,6 @@ vbf_stp_retry(struct worker *wrk, struct busyobj *bo)
 	bo->storage = NULL;
 	bo->do_esi = 0;
 	bo->do_stream = 1;
-	bo->filter_list = NULL;
 	bo->was_304 = 0;
 
 	// XXX: BereqEnd + BereqAcct ?