[libvirt] Incomplete stdout returned by qemu -help cause kvm disabled

Hi: In our setup(libvirt 0.9.9 with Arch Linux with kernel 3.2+), when libvirt are accessed simultaneously, say 8 createDomain requests, there is a large chance that `qemu -help` return incomplete stdout which cause kvm to be disabled. Another user have the same situation like us[1] and he suspected this being the result of some race conditions. 1: https://www.redhat.com/archives/libvir-list/2012-April/msg00380.html -- lei yang