Comment 20 for bug 8058

Actually, to be honest on another reading I don't see how the existing warning
when you try to do this isn't clear:

  Your root filesystem is an XFS filesystem. This is likely to cause problems
with the GRUB bootloader used by default with this installer; you might
experience problems installing or booting GRUB.

  You should use a small /boot partition with another filesystem, such as ext3.

  Use unrecommended XFS boot filesystem?

I'm not saying it's not a bug, but I think we can consider it not
release-critical. Matt?