Disable slapos.zcbworkarounds and slapos.rebootstrap.

Those extensions are only good in case of extremely complex profiles.

software/kumofs/software.cfg

 [buildout]
-
-extensions =
-  slapos.zcbworkarounds
-  slapos.rebootstrap
-
 find-links +=
     http://www.nexedi.org/static/packages/source/slapos.buildout/
 
@@ -44,11 +39,6 @@ parts +=
 # development / fast switching environment for whole software
 unzip = true
 
-[rebootstrap]
-# Default first version of rebootstrapped python
-version = 2
-section = python2.7
-
 [instance-recipe]
 egg = slapos.cookbook
 module = kumofs