Description of problem:

# xm create -c rhel4pv
Using config file "/etc/xen/rhel4pv".
Traceback (most recent call last):
  File "/usr/bin/pygrub", line 258, in ?
    curses.wrapper(run_main)
  File "/usr/lib/python2.4/curses/wrapper.py", line 44, in wrapper
    return func(stdscr, *args, **kwds)
  File "/usr/bin/pygrub", line 214, in run_main
    sel = main(cf)
  File "/usr/bin/pygrub", line 164, in main
    selected = cf.default
  File "/usr/lib/python2.4/site-packages/grub/GrubConf.py", line 193, in
_get_default
    return self._default
AttributeError: 'GrubConfigFile' object has no attribute '_default'
Error: Boot loader didn't return any data!

Version-Release number of selected component (if applicable):

xen-3.0.2-0.FC5.1

Steps to reproduce:
1. install fully virtualized guest
2. install paravirtualized kernel inside it
3. remove default=1 line from grub.conf
4. try to boot the domain in paravirt, get above error message
5. boot the domain in HVM mode, normal grub works fine
6. edit grub.conf add back default=0 line
7. now pygrub is happy again