Fix return value

homeassistant/components/sensor/openweathermap.py

@@ -91,7 +91,7 @@ def setup_platform(hass, config, add_devices, discovery_info=None):
         _LOGGER.error(
             "Connection error "
             "Please check your settings for OpenWeatherMap.")
-        return None
+        return False
 
     data = WeatherData(owm, forecast, hass.config.latitude,
                        hass.config.longitude)