Document that error is shown by %{Varnish:handling} in varnishncsa too

git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@5550 d4fa192b-c00b-0410-8231-f00ffab90ce4

doc/sphinx/reference/varnishncsa.rst

@@ -102,7 +102,7 @@ The following options are available:
 
 		   Varnish:handling
 		     How the request was handled, whether it was a
-		     cache hit, miss, pass or pipe.
+		     cache hit, miss, pass, pipe or error.
 
 -o	    Filter log output to request groups that match a regular
 	    expression on a specified tag.