[Samba] Migrate from sernet-samba to samba4

[Tim ODriscoll]

On 25 May 2017 10:11:
> You can however easily get the source and compile Samba yourself. Just 
> look in the wiki for the prerequisites for centOS7. It is one huge "yum 
> install" command, mostly for some libraries. I just compiled it on 
> Scientific Linux 6 after the exact same command.

Excellent, thank you for the pointer..

Tim