Use mkfs.ext3 to make ext3 filesystem instead of ext4

Change-Id: I42c37ed1e0e41babe9589be2df39ccbf22385458
diff --git a/y2019/vision/tools/flash.sh b/y2019/vision/tools/flash.sh
index 5cef493..d3c55ae 100755
--- a/y2019/vision/tools/flash.sh
+++ b/y2019/vision/tools/flash.sh
@@ -31,7 +31,7 @@
 fi
 
 # need to disable some new features on 17.x
-sudo mkfs.ext4 -L JEVOIS -O ^64bit,uninit_bg,^metadata_csum ${DEV_BASE}3
+sudo mkfs.ext3 -L JEVOIS ${DEV_BASE}3
 
 echo "Mounting JEVOIS."
 mkdir -p /tmp/JEVOIS