doc: README: specify configuration of kerberos in oVirt 4.0
doc: README: specify configuration of kerberos in oVirt 4.0

Change-Id: Ie5a87f3c117a05d7c03c170d18dd0b3ba8162a51
Signed-off-by: Ondra Machacek <e60c747dda196805269ffcf3f8efbe65520b6f6b@redhat.com>

oVirt/ovirt-engine-extension-aaa-ldap,oVirt/ovirt-engine-extension-aaa-ldap,oVirt/ovirt-engine-extension-aaa-ldap