Description of problem:

At the moment we are carrying two non-upstream patches
in Fedora:
http://pkgs.fedoraproject.org/gitweb/?p=libguestfs.git;a=tree;h=refs/heads/f16;hb=refs/heads/f16

But we should detect this and deal with it automatically.

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

1.13.23

How reproducible:

100%

Steps to Reproduce:
1. Install qemu 0.15 and upstream libguestfs.
2. Try libguestfs-test-tool.
3.
  
Actual results:

Fails with this error:
[00146ms] /usr/bin/kvm \
    -drive file=/tmp/libguestfs-test-tool-sda-1vJL7p,cache=off,format=raw,if=virtio \
    -nodefconfig \
    -machine accel=kvm:tcg \
    -nodefaults \
    -nographic \
    -m 500 \
    -no-reboot \
    -no-hpet \
    -device virtio-serial \
    -serial stdio \
    -chardev socket,path=/tmp/libguestfsbx1uQx/guestfsd.sock,id=channel0 \
    -device virtserialport,chardev=channel0,name=org.libguestfs.channel.0 \
    -kernel /var/tmp/.guestfs-1000/kernel.26409 \
    -initrd /var/tmp/.guestfs-1000/initrd.26409 \
    -append 'panic=1 console=ttyS0 udevtimeout=300 noapic no_timer_check acpi=off printk.time=1 cgroup_disable=memory selinux=0 guestfs_verbose=1 TERM=screen ' \
    -drive file=/var/tmp/.guestfs-1000/root.26409,snapshot=on,if=virtio,cache=unsafeSupported machines are:
pc         Standard PC (alias of pc-0.14)
pc-0.14    Standard PC (default)
pc-0.13    Standard PC
pc-0.12    Standard PC
pc-0.11    Standard PC, qemu 0.11
pc-0.10    Standard PC, qemu 0.10
isapc      ISA-only PC
libguestfs: child_cleanup: 0x2486990: child process died
libguestfs: error: child process died unexpectedly
libguestfs-test-tool: failed to launch appliance
libguestfs: closing guestfs handle 0x2486990 (state 0)

Expected results:

Should detect this situation and work around it.

Additional info:

Note there are several versions of qemu with different
behaviours (no surprise there).