qemu: Fix job usage in virDomainGetBlockIoTune
qemu: Fix job usage in virDomainGetBlockIoTune

CVE-2013-6458

Every API that is going to begin a job should do that before fetching
data from vm->def.

(cherry picked from commit 3b56425938e2f97208d5918263efa0d6439e4ecd)

Conflicts:
	src/qemu/qemu_driver.c - older BeginJobWithDriver

Signed-off-by: Jiri Denemark <62bdf77dc47919a4d59a91822129d14633cfca81@redhat.com>

mithleshvrts/libvirt-0.10.2,mithleshvrts/libvirt-0.10.2,mithleshvrts/libvirt-0.10.2,mithleshvrts/libvirt-0.10.2,mithleshvrts/libvirt-0.10.2