[Samba] Provisioning new AD Domain Controller

[Mark Foley]

Because of issues described in thread "Joining Windows 10 Domain Member to Samba
AD/DC", I'm trying to re-provision my DC with the curren/old domain name
mail.hprs.local instead of the newer, more correct dc1.hprs.locl.

I've followed the steps in 

https://wiki.samba.org/index.php/Setting_up_Samba_as_an_Active_Directory_Domain_Controller

regarding "Only Applicable if Samba was Previously Installed". For the directory
list:

# smbd -b | egrep "LOCKDIR|STATEDIR|CACHEDIR|PRIVATE_DIR"
   LOCKDIR: /var/cache/samba
   STATEDIR: /var/lib/samba
   CACHEDIR: /var/cache/samba
   PRIVATE_DIR: /var/lib/samba/private

I did 'rm -r /var/cache/samba* /var/lib/samba/*'. I then did the provision step
again:

samba-tool domain provision --use-rfc2307 --realm=HPRS.LOCAL --domain=HPRS \
  --server-role=dc --dns-backend=SAMBA_INTERNAL --option=interfaces="lo eth0" \
  --option="bind interfaces only=yes" --adminpass=pw

However, when I got to the 'samba-tool dns zonelist' step, I got:

Password for [administrator at HPRS.LOCL]:

Notice that it is asking for the supposedly purged realm HPRS.LOCL. There must
be more that needs to be removed other than just those egrep'ed directories.

/etc/hosts is:

127.0.0.1               localhost
192.168.1.60             mail.hprs.local mail

/etc/HOSTNAME is:

mail.hprs.local

The generated smb.conf is:

# Global parameters
[global]
        bind interfaces only = Yes
        dns forwarder = 192.168.1.1
        interfaces = lo eth0
        netbios name = MAIL
        realm = HPRS.LOCAL
        server role = active directory domain controller
        workgroup = HPRS
        idmap_ldb:use rfc2307 = yes

[sysvol]
        path = /var/lib/samba/sysvol
        read only = No

[netlogon]
        path = /var/lib/samba/sysvol/hprs.local/scripts
        read only = No


There are no other .tdb or .ldb files on the drive.

Where is this old realm name lurking, why is it associated with the
Administrator and how do I purge it and any remaining such vestigal
references without scratch-installing Linux?

Thanks --Mark