Add the device_smart_healthy metric

roles/float-base/files/node-exporter-scripts/smartmon.py

@@ -251,6 +251,7 @@ def collect_device_metrics(device):
     if not is_available:
         return
 
+    yield Gauge('device_smart_healthy', device.labels, data['smart_status']['passed'])
     yield Gauge('power_on_hours', device.labels, data['power_on_time']['hours'])
     yield Gauge('power_cycle_count', device.labels, data['power_cycle_count'])