I have my hard disks configured as follows:

sda1: NTFS - system partition for Win7 x64
sda2: NTFS - user data partition
sdb1: ext4 - system partition for Bodhi Linux
sdb2: NTFS - more user data

When I run update-grub I get this:

> sudo update-grub
Generating grub.cfg ...
Found linux image: /boot/vmlinuz-3.8.0-12-generic
Found initrd image: /boot/initrd.img-3.8.0-12-generic
Found Windows 7 (loader) on /dev/sda1
Found MS-DOS 5.x/6.x/Win3.1 on /dev/sda2
There is, of course, no MS-DOS or Win3.1 system on /dev/sda2. The additional useless line in grub2 is hardly a show-stopping problem, but I'd still rather remove it. How do I do that? I've had a look in /etc/grub.d/##_whatever but I can't see the relevant lines.