Force dns module restart after provision

The restart is forced to regen the configuration and load the domain dns zone
from samba
Remove workaround for DNS spn

The workaround create the DNS spn, assign it to the machine account and
extracted it to the dns.keytab for its use by bind when joining a domain.
This issue has been fixed upstream so the workaround can be removed.
Wait for RID set allocation after join domain

Backported from 3.2. It waits for RID set to be assigned to the local server
after join a domain before create the modules SPNs like HTTP, IMAP or SMTP
Bump samba4 dependency version
Merge pull request #1197 from Zentyal/scabrero/samba-fix-provision

Scabrero/samba fix provision