Revert "[health_checker] Disable reboot logic"

This reverts commit b3f5b19520fa9012f4cea76ca5d67b81bc2aab6a.

Reason for revert: <INSERT REASONING HERE>

Original change's description:
> [health_checker] Disable reboot logic
> 
> Change-Id: I33dc81440627ea5ea8626ec4262d2f8c8ada5a23

TBR=nsylvain@google.com,nmulcahey@google.com,ihuh@google.com

Change-Id: Ia8180032f4f62007655d8177741b9dd94c1cede3
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
diff --git a/cmd/health_checker/main.go b/cmd/health_checker/main.go
index bca9d30..51abf02 100644
--- a/cmd/health_checker/main.go
+++ b/cmd/health_checker/main.go
@@ -128,11 +128,11 @@
 			log.Fatal("Failed to retrieve nodename from config file")
 		}
 		checkResult := checkHealth(client, nodename)
-		// if checkResult.State == unhealthyState && rebootIfUnhealthy {
-		// 	if rebootErr := reboot(deviceProperties); rebootErr != nil {
-		//		checkResult.ErrorMsg += "; " + rebootErr.Error()
-		//	}
-		// }
+		if checkResult.State == unhealthyState && rebootIfUnhealthy {
+			if rebootErr := reboot(deviceProperties); rebootErr != nil {
+				checkResult.ErrorMsg += "; " + rebootErr.Error()
+			}
+		}
 		checkResultSlice = append(checkResultSlice, checkResult)
 	}
 	if err = printHealthCheckResults(checkResultSlice); err != nil {