[health_checker] Increase timeout for discovering device address.

If health_checker is called too soon after device has been rebooted, it
will return an unhealthy state even though it is fine. I'm increasing
the timeout to reduce these occurrences.

Change-Id: I308512d85c4be9ba729d84c16389c72e2b9208cf
diff --git a/cmd/health_checker/main.go b/cmd/health_checker/main.go
index 691fae8..51abf02 100644
--- a/cmd/health_checker/main.go
+++ b/cmd/health_checker/main.go
@@ -108,7 +108,7 @@
 	// First set the flags ...
 	flag.StringVar(&configFile, "config", "/etc/botanist/config.json",
 		"The path of the json config file that contains the nodename of the device. Format is defined in https://fuchsia.googlesource.com/tools/+/master/botanist/common.go")
-	flag.DurationVar(&timeout, "timeout", 3*time.Second,
+	flag.DurationVar(&timeout, "timeout", 10*time.Second,
 		"The timeout for checking each device. The format should be a value acceptable to time.ParseDuration.")
 	flag.BoolVar(&rebootIfUnhealthy, "reboot", false, "If true, attempt to reboot the device if unhealthy.")
 }