samba4: upgradeprovision --full fails

[srikumar 108]

Following up on my own post:

> Starting update of samdb
> There are 1 missing objects
> Object CN=dns-lucid,CN=Users,DC=test,DC=com will be added

Upon restart, dns.keytab is now empty and hence, dns update is toast.
I did notice that secrets.ldb now has an entry named dns-<hostname>
after update, but there is no corresponding entry in sam.ldb.