Upgrade to CentOS 7.2

a.k.a. CentOS Linux release 7.2.1511 (Core) with Kernel 3.10.0-327.3.1.el7.x86_64.
The most difficult part was the upgrade of the Timemachine backup server, because of the netatalk paackage.
I ended with building the netatalk RPMs from source on the Centos Desktop VM on my Mac Mini.
I then uploaded the RPMs to the my Nexus instance and was able to upgrade.