giuseppe/ppc64

fixes to get io-github-autotest-qemu.unattended_install.cdrom.extra_cdrom_ks.default_install.aio_native working on ppc64:

./run -t qemu --no-downloads --keep-image --qemu_sandbox off -g Linux.Fedora.20.ppc64.pseries --tests io-github-autotest-qemu.unattended_install.cdrom.extra_cdrom_ks.default_install.aio_native