Fix for grub 2.00/bzr kfreebsd to boot 9.1 kernels

Hi!

 I'm in the process of testing 9.1 on the laptop where I use grub2
because I had to put bsd in an `extended' slice, and I found out
grub2 won't boot the 9.1 kernel.  Asked on #grub where phcoder
found the fix after I made him a test iso using grub-mkrescue:

	http://paste.debian.net/180121/

Applied that to grub 2.00 from here:

	http://ftp.gnu.org/gnu/grub/grub-2.00.tar.xz

(built on a Linux debian slice with checkinstall), and that got
the 9.1 kernel booting.  So maybe the sysutils/grub2 maintainer
(Cc'd) wants to update the port to 2.00 and add the patch in
files/? :)  (It's still at 1.98 currently where the patch doesn't
apply.)

 The kfreebsd way to boot this affects is the same as in this
earlier post:

	http://lists.freebsd.org/pipermail/freebsd-multimedia/2011-March/011828.html

(i.e. this is not chainloading bsd's loader but grub loading the
kernel and klds itself.  I think this way to boot was originally
added by the debian kfreebsd guys, hence the command kfreebsd...)

 HTH,
	Juergen