[yocto] Y-AB automatic updates?

[gmane at reliableembeddedsystems.com]

Hi,

With a latest and greatest Yocto Autobuilder I noticed stuff like this 
when I restart it:

---
...
  Updating PRSERV
remote: Counting objects: 20, done.
remote: Compressing objects: 100% (20/20), done.
remote: Total 20 (delta 17), reused 0 (delta 0)
Unpacking objects: 100% (20/20), done.
 From git://git.openembedded.org/bitbake
    35927a9..d9713ed  master     -> origin/master
    35927a9..d9713ed  1.32       -> origin/1.32
  + 21defce...09dd499 master-next -> origin/master-next  (forced update)
Updating 35927a9..d9713ed
Fast-forward
  bin/bitbake         |  2 +-
  lib/bb/__init__.py  |  2 +-
  lib/bb/ui/depexp.py | 24 ++++++++++++++++++++++++
  3 files changed, 26 insertions(+), 2 deletions(-)

---

This pumps e.g. the bitbake version:

Author: Richard Purdie <richard.purdie at linuxfoundation.org>
Date:   Tue Oct 11 08:46:35 2016 +0100

     bitbake: Update version to 1.32.0

---

Is this really intentionally and what's the purpose?

Say you have a build server for your production software and PRSERV is 
being (randomly) updated.
Due to a bug before or after the update the build output might be 
different.
So you can't reproduce your images any more.

Some people (including myself) really would like to have reproduce able 
builds.

Is there a "non hacky" way to turn these updates off?

Regards,

Robert