[master] 7d7c8ab add ban and ban_url

[Per Andreas Buer]

commit 7d7c8abdb2621da0d7174e5bfef43f5af452d29a
Author: Per Buer <perbu at varnish-software.com>
Date:   Thu May 19 12:37:44 2011 +0200

    add ban and ban_url

diff --git a/doc/sphinx/reference/vcl.rst b/doc/sphinx/reference/vcl.rst
index 85553f4..8837142 100644
--- a/doc/sphinx/reference/vcl.rst
+++ b/doc/sphinx/reference/vcl.rst
@@ -323,8 +323,11 @@ regsub(str, regex, sub)
 regsuball(str, regex, sub)
   As regsuball() but this replaces all occurrences.
 
-purge_url(regex)
-  Purge all objects in cache whose URLs match regex.
+ban(ban expression)
+  Executes a ban.
+
+ban_url(regex)
+  Bans all objects in cache whose URLs match regex.
 
 Subroutines
 ~~~~~~~~~~~