[4.0] 3c33b93 Forgot to change error -> synth here.

[Poul-Henning Kamp]

commit 3c33b93461793ad69c5a3aa644b44f3c64e07855
Author: Poul-Henning Kamp <phk at FreeBSD.org>
Date:   Tue Mar 18 16:42:36 2014 +0000

    Forgot to change error -> synth here.

diff --git a/bin/varnishd/builtin.vcl b/bin/varnishd/builtin.vcl
index cdac8d9..5ac9664 100644
--- a/bin/varnishd/builtin.vcl
+++ b/bin/varnishd/builtin.vcl
@@ -91,7 +91,7 @@ sub vcl_hash {
 }
 
 sub vcl_purge {
-    return (error(200, "Purged"));
+    return (synth(200, "Purged"));
 }
 
 sub vcl_hit {