qemu: Don't update count of vCPUs if hot-unplug has failed
qemu: Don't update count of vCPUs if hot-unplug has failed

https://bugzilla.redhat.com/show_bug.cgi?id=895424

After live change of cpu counts, the number of processor threads is
verified. This patch makes use of this approach to check if qemu ignored
the request for cpu hot-unplug and report an appropriate message.
(cherry picked from commit 761fc481365703b861429d73a341bde352ba8d41)

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