Description of problem:
Grub2 cfgfile was added to Xen pygrub in here: https://bugzilla.redhat.com/show_bug.cgi?id=577511 . It works OK for Ubuntu 10.04 LTS but fails for new Debian 6.0 Squeeze. Debian uses a newer version of grub2 with a slightly different syntax.

Version-Release number of selected component (if applicable):
xen-3.0.3-120.el5

How reproducible:
Always.

Steps to Reproduce:
1. Install RHEL5.6 Xen dom0
2. Install Debian 6.0 Squeeze PV domU using the debian installer.
3. After installation try to boot it using pygrub.
  
Actual results:

# xm create -f debian1.cfg -c
Using config file "./debian1.cfg".
Using <class 'grub.GrubConf.Grub2ConfigFile'> to parse /boot/grub/grub.cfg
WARNING:root:Unknown directive load_video
WARNING:root:Unknown directive terminal_output
Traceback (most recent call last):
  File "/usr/bin/pygrub", line 691, in ?
    chosencfg = run_grub(file, entry, fs)
  File "/usr/bin/pygrub", line 545, in run_grub
    g = Grub(file, fs)
  File "/usr/bin/pygrub", line 203, in __init__
    self.read_config(file, fs)
  File "/usr/bin/pygrub", line 407, in read_config
    self.cf.parse(buf)
  File "/usr/lib64/python2.4/site-packages/grub/GrubConf.py", line 401, in parse
    self.add_image(Grub2Image(title, img))
  File "/usr/lib64/python2.4/site-packages/grub/GrubConf.py", line 318, in __init__
    _GrubImage.__init__(self, title, lines)
  File "/usr/lib64/python2.4/site-packages/grub/GrubConf.py", line 84, in __init__
    self.reset(lines)
  File "/usr/lib64/python2.4/site-packages/grub/GrubConf.py", line 102, in reset
    self._parse(lines)
  File "/usr/lib64/python2.4/site-packages/grub/GrubConf.py", line 96, in _parse
    map(self.set_from_line, lines)
  File "/usr/lib64/python2.4/site-packages/grub/GrubConf.py", line 328, in set_from_line
    setattr(self, self.commands[com], arg.strip())
  File "/usr/lib64/python2.4/site-packages/grub/GrubConf.py", line 105, in set_root
    self._root = GrubDiskPart(val)
  File "/usr/lib64/python2.4/site-packages/grub/GrubConf.py", line 54, in __init__
    (self.disk, self.part) = str.split(",", 2)
  File "/usr/lib64/python2.4/site-packages/grub/GrubConf.py", line 79, in set_part
    self._part = int(val)
ValueError: invalid literal for int(): msdos1
No handlers could be found for logger "xend"
Error: Boot loader didn't return any data!



Expected results:
pygrub works and domU starts fine.

Additional info:

grub2 grub.cfg menuentry from Debian 6.0 (Squeeze):

menuentry 'Debian GNU/Linux, with Linux 2.6.32-5-686-bigmem' --class debian --class gnu-linux --class gnu --class os {
        insmod part_msdos
        insmod ext2
        set root='(hd0,msdos1)'
        search --no-floppy --fs-uuid --set 5e7e881f-9f52-40e4-a74e-65cc87cf1cbc
        echo    'Loading Linux 2.6.32-5-686-bigmem ...'
        linux   /boot/vmlinuz-2.6.32-5-686-bigmem root=UUID=5e7e881f-9f52-40e4-a74e-65cc87cf1cbc ro console=hvc0 quiet
        echo    'Loading initial ramdisk ...'
        initrd  /boot/initrd.img-2.6.32-5-686-bigmem
}



grub2 grub.cfg menuentry from Ubuntu 10.04 LTS (this works OK):

menuentry 'Ubuntu, with Linux 2.6.32-30-generic' --class ubuntu --class gnu-linux --class gnu --class os {
        recordfail
        insmod ext2
        set root='(hd0,1)'
        search --no-floppy --fs-uuid --set 75ec40b9-050f-4fbd-91ce-9b14cd28a18a
        linux   /boot/vmlinuz-2.6.32-30-generic root=UUID=75ec40b9-050f-4fbd-91ce-9b14cd28a18a ro console=hvc0  splash quiet
        initrd  /boot/initrd.img-2.6.32-30-generic
}


Upstream Xen has patches to fix pygrub for Debian 6.0 Squeeze.