I'll try to give some more details, I'm cannot verify every detail as I'm not at my home:
You have to log in to the console of either the MD or the core. On the MD press ctrl+alt+f1 to get to a console. log in as root, no password should be required. type
nano /etc/fstab If this editor (nano) is not installed, you will be told that. To install it type
apt-get install nano.
Find the line and change it.
Ctrl+o to save, ctrl+x to exit.
You could try umount and then mount the /home share to apply the new settings but it might be as easy to just reboot.
hope this helps,