[health checker] Disable fastboot in health checks

I disabled powercycling into fastboot when fastboot was disabled but
did not fix the corresponding health checks.

Change-Id: Idc76040eae80bdc27994e0bdf531a6dc2ef2a4ee
Reviewed-on: https://fuchsia-review.googlesource.com/c/infra/infra/+/389275
Reviewed-by: Nathan Mulcahey <nmulcahey@google.com>
Commit-Queue: Anirudh Mathukumilli <rudymathu@google.com>
diff --git a/cmd/health_checker/main.go b/cmd/health_checker/main.go
index 33fd52f..9e92ff2 100644
--- a/cmd/health_checker/main.go
+++ b/cmd/health_checker/main.go
@@ -134,7 +134,7 @@
 func checkHealth(ctx context.Context, n *netboot.Client, device *devicePkg.DeviceTarget) HealthCheckResult {
 	nodename := device.Nodename()
 	log.Printf("Checking health for %s", nodename)
-	if device.Type() == "astro" || device.Type() == "sherlock" {
+	if enableFastboot && (device.Type() == "astro" || device.Type() == "sherlock") {
 		if err := checkIfInFastboot(ctx, device); err != nil {
 			return HealthCheckResult{nodename, unhealthyState, err.Error()}
 		}