[6.0] 8c902af1e vsl: Kill dead check

[Martin Blix Grydeland]

commit 8c902af1e38f664fa42d35be845a4129d9589817
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Wed Oct 28 15:31:33 2020 +0100

    vsl: Kill dead check
    
    There's only one call site for vtx_dispatch() and it guarantees that len
    is greater than zero.

diff --git a/lib/libvarnishapi/vsl_dispatch.c b/lib/libvarnishapi/vsl_dispatch.c
index 0075e2322..ebc45123a 100644
--- a/lib/libvarnishapi/vsl_dispatch.c
+++ b/lib/libvarnishapi/vsl_dispatch.c
@@ -435,8 +435,7 @@ vtx_append(struct VSLQ *vslq, struct vtx *vtx, const struct VSLC_ptr *start,
 	enum vsl_check i;
 
 	AN(vtx);
-	if (len == 0)
-		return;
+	AN(len);
 	AN(start);
 
 	i = VSL_Check(vslq->c, start);