Fix apcupsd spamming logs when host is unavailable (#85920)

fixes undefined

homeassistant/components/apcupsd/binary_sensor.py

@@ -65,8 +65,15 @@ class OnlineStatus(BinarySensorEntity):
 
     def update(self) -> None:
         """Get the status report from APCUPSd and set this entity's state."""
-        self._data_service.update()
+        try:
+            self._data_service.update()
+        except OSError as ex:
+            if self._attr_available:
+                self._attr_available = False
+                _LOGGER.exception("Got exception while fetching state: %s", ex)
+            return
 
+        self._attr_available = True
         key = self.entity_description.key.upper()
         if key not in self._data_service.status:
             self._attr_is_on = None