virt-handler: cgroup: use io.Copy instead of reimplementing it
virt-handler: cgroup: use io.Copy instead of reimplementing it

Signed-off-by: Marcelo Tosatti <958bcd1f4a7a8c36dca09fe3fa9cb5f1483adf51@redhat.com>

kubevirt/kubevirt,kubevirt/kubevirt,kubevirt/kubevirt,kubevirt/kubevirt