follow setpoint: state to OK for received device setpoit but no target value

z_server/devices/__init__.py

                 tm_t, value_t = self.__target_storage__[self.FOLLOW_KEY]
             except KeyError:
                 if value_s is not None:
-                    return self.__nagios_return__(self.MONITORING_FOLLOW_SETPOINT, nagios.Nagios.WARNING, "Current temperature setpoint %.1f°C (age=%.1fmin), but never received a setpoint" % (value_s, (time.time()-tm_s)/60))
+                    return self.__nagios_return__(self.MONITORING_FOLLOW_SETPOINT, nagios.Nagios.OK, "Current temperature setpoint %.1f°C (age=%.1fmin), but never received a setpoint. That might be okay." % (value_s, (time.time()-tm_s)/60))
                 return self.__nagios_return__(self.MONITORING_FOLLOW_SETPOINT, nagios.Nagios.UNKNOWN, "Device exists, but no data received")
             else:
                 tm = time.time()