samba-tool domain demote: Allow to operate on an RODC and a subdomain

samba-tool domain demote: Allow to operate on an RODC and a subdomain

On an RODC the local database cannot be modified, and the flags to remove
are different, we need instead to remove UF_PARTIAL_SECRETS_ACCOUNT.

If we are in a subdomain, then db.get_root_basedn() points to the
forest root, not the root of our domain

If the removeDsServer() fails with WERR_DS_DRA_NO_REPLICA
this may be reasonably considered to be success in this case.

Finally, the remove_dc.remove_sysvol_references() is reused
for objects not under the computer account.

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>
domain demote

Signed-off-by: Andrew Bartlett <abartlet@samba.org>
Reviewed-by: Garming Sam <garming@catalyst.net.nz>