Fix example to new backend syntax

git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@2448 d4fa192b-c00b-0410-8231-f00ffab90ce4

man/vcl.7

@@ -80,8 +80,8 @@ keyword followed by the name of the other file as a quoted string.
 A backend declaration creates and initializes a named backend object:
 .Bd -literal -offset 4n
 backend www {
-    set backend.host = "www.example.com";
-    set backend.port = "http";
+    .host = "www.example.com";
+    .port = "http";
 }
 .Ed
 .Pp