Handle case of non-present leds in preflight check

src/systemcmds/preflight_check/preflight_check.c

@@ -135,6 +135,7 @@ int preflight_check_main(int argc, char *argv[])
 
 	close(fd);
 	fd = open(BARO_DEVICE_PATH, 0);
+	close(fd);
 
 	/* ---- RC CALIBRATION ---- */
 
@@ -251,6 +252,11 @@ system_eval:
 		int buzzer = open("/dev/tone_alarm", O_WRONLY);
 		int leds = open(LED_DEVICE_PATH, 0);
 
+		if (leds < 0) {
+			close(buzzer);
+			errx(1, "failed to open leds, aborting");
+		}
+
 		/* flip blue led into alternating amber */
 		led_off(leds, LED_BLUE);
 		led_off(leds, LED_AMBER);