[master] c661da5 Mention the use of std.rollback() to reset req.http.* in "Upgrading".

[Geoff Simmons]

commit c661da5e5fc51473da0e0b701075dbaf72c249d3
Author: Geoff Simmons <geoff at uplex.de>
Date:   Wed Mar 14 21:13:57 2018 +0100

    Mention the use of std.rollback() to reset req.http.* in "Upgrading".

diff --git a/doc/sphinx/whats-new/upgrading-6.0.rst b/doc/sphinx/whats-new/upgrading-6.0.rst
index fce4ded..21ddbf0 100644
--- a/doc/sphinx/whats-new/upgrading-6.0.rst
+++ b/doc/sphinx/whats-new/upgrading-6.0.rst
@@ -457,6 +457,10 @@ Restarts now leave all of the properties of the client request
 unchanged (all of the ``req.*`` variables, including the headers),
 except for ``req.restarts`` and ``req.xid``, which change by design.
 
+If you need to reset the client request headers to their original
+state (before changes in VCL), call
+:ref:`std.rollback(req) <func_rollback>`.
+
 ``return(restart)`` can now be called from ``vcl_recv{}``.
 
 New VMODs