configure realmd to allow login without domain name

Changes made to realmd.conf only take affect when joining a domain or realm.

You'll need to either leave and join the domain again, or make the requisite changes to winbind or sssd.

For example, with sssd, you would edit /etc/sssd/sssd.conf and set use_fully_qualified_names to false.

If you want to add the default domain suffix so you don't have to type every time you type your username, run

sed -i '/nss,/a default_domain_suffix = CONTOSO.COM' /etc/sssd/sssd.conf