update changelog and version for 2.5.2+slapos013

CHANGES.SlapOS.rst

+2.5.2+slapos13
+--------------
+- Exit program with error code on error when running with ``-D`` (backport).
+
 2.5.2+slapos12
 --------------
 

setup.py

@@ -12,7 +12,7 @@
 #
 ##############################################################################
 name = "zc.buildout"
-version = '2.5.2+slapos012'
+version = '2.5.2+slapos013'
 
 import os
 from setuptools import setup

[Jérome Perrin]

I listed as backport because it's also https://github.com/buildout/buildout/pull/465 ( from 2.12.2 )