Never mind about filing the bug; I have pushed this commit:
http://git.annexia.org/?p=libguestfs.git;a=commitdiff;h=54e91da925323642e...
Rich.
--
Richard Jones, Virtualization Group, Red Hat
http://people.redhat.com/~rjones
virt-df lists disk usage of guests without needing to install any
software inside the virtual machine. Supports Linux and Windows.
http://et.redhat.com/~rjones/virt-df/