[master] 70d37c5 Breaking change

[Dridi Boukelmoune]

commit 70d37c569442ec531fa15f10008224dbe66f5f96
Author: Dridi Boukelmoune <dridi.boukelmoune at gmail.com>
Date:   Mon Mar 13 14:30:35 2017 +0100

    Breaking change

diff --git a/doc/sphinx/whats-new/changes-5.1.rst b/doc/sphinx/whats-new/changes-5.1.rst
index 3a81cde..1a56bbf 100644
--- a/doc/sphinx/whats-new/changes-5.1.rst
+++ b/doc/sphinx/whats-new/changes-5.1.rst
@@ -233,7 +233,8 @@ in the project.
 The ``varnishtest`` program has been improved in many small ways,
 in particular it is now much easier to execute and examine
 results from other programs with the ``shell`` and ``process``
-commands.
+commands. It might break existing test cases if you were already
+using ``varnishtest``.
 
 The project now has *KISS* web-backend which summarizes 
 ``make distcheck`` results from various platforms: