LDAP: Enable tokenGroups with Windows Server 2003
According to Microsoft documentation, the tokenGroups attribute is
available since Windows 2000:
http://msdn.microsoft.com/en-us/library/cc220937.aspx
We were not able to test against Windows 2000, though, as we don't have
that OS around, so this patch only changes the compatibility level to
2003.
Reviewed-by: Pavel Březina <pbrezina@redhat.com>