grub2 os_prober bug

[Tim H]

I am not sure if this is Xubuntu specific, however, if recovering an 
installation in the event of a drive failure, the UUID is reset, of 
course.  However, the the os_prober reads the UUID from another OS's 
boot/grub.cfg file, rather than from the current root's 
dev/disk/by-uuid.  This means old UUID's are used on "other" OS 
installations.

This seemed odd at first, but proven to be correct by removing the 
secondary installation's boot/grub.cfg and running update-grub once 
again.  The UUID corrected itself.

I can open a bug with Grub if anyone can confirm this wasn't something 
setup by the xubuntu dev team.

Tim