I tried this tutorial twice and both times couldn't SSH in after the final reboot. I found this tutorial a little more helpful - http://petr.io/en/blog/2015/11/09/read-only-raspberry-pi-with-jessie/. I susptec the difference was the part they mentione specifically enables SSH after changing these settings. That tutorial also makes it a little more clear that you have to add three lines in /etc/fstab, not just add ro twice.