update of dns method

dns.py

def get_dnsaas(token, **kwargs):
    """
    Return a instance of the DNSaaS.
    A new instance is deployed if don't exist one
    :param token: The token
    """
    if kwargs['tenant_name'] is not None:
        tenant = kwargs['tenant_name']
    else:
        tenant = 'demo'

    if kwargs['dns_endpont'] is not None:
        endpoint = kwargs['dns_endpont']
        dns_action = DNSaaSClientCore  # TODO this needs to be the client as used in the DSS
        return dns_action
    else:
        endpoint = services.get_service_endpoint('http://schemas.mobile-cloud-networking.eu/occi/sm#dnsaas',
                                                 token, **kwargs)
        if endpoint is None:
            print ("Error: Initiate the SM")
            return None
        else:
            maas_address=None
            maas_endpoint=None
            dispose_maas=False
            dns_action = dnsaasclient.DNSaaSClientAction(endpoint, tenant, token, maas_address, maas_endpoint, dispose_maas)
            if dns_action.init_dns():
                return dns_action
            else:
                return None