[6.0] a056f9981 Migrate the shell PID to haproxy where we want it.

[Poul-Henning Kamp]

commit a056f9981e23d16f17e3149dd2c0fa23b29ba0ae
Author: Poul-Henning Kamp <phk at FreeBSD.org>
Date:   Wed Mar 28 14:16:00 2018 +0000

    Migrate the shell PID to haproxy where we want it.

diff --git a/bin/varnishtest/vtc_haproxy.c b/bin/varnishtest/vtc_haproxy.c
index d97ffb47d..e3ea8d22d 100644
--- a/bin/varnishtest/vtc_haproxy.c
+++ b/bin/varnishtest/vtc_haproxy.c
@@ -283,7 +283,7 @@ haproxy_start(struct haproxy *h)
 
 	vsb = VSB_new_auto();
 	AN(vsb);
-	VSB_printf(vsb, "%s %s", h->filename, VSB_data(h->args));
+	VSB_printf(vsb, "exec %s %s", h->filename, VSB_data(h->args));
 
 	if (h->opt_worker || h->opt_daemon) {
 		bprintf(buf, "%s/pid", h->workdir);