Add function: conn.rename(dn, new_rdn, new_parent_dn, delete_old_rdn, sctrls, cctrls)  => self
 Modify the RDN of the entry with DN, dn, giving it the new RDN in parent new_parent_dn,
 new_rdn. If delete_old_rdn is true, the old RDN value will be deleted from the entry