[libvirt] cgroup limits only affect kvm guest under certain conditions

[Dominik Klein]

> qemu consists of several threads. Cgroup works per thread now.
> Could you double check "all threads for qemu" are in a cgroup ?
> I think you have to write all thread-ID to "tasks" file when you
> move qemu after starting it.

As stated yesterday: Yes, that was the problem. Works as expected now,
thanks.

Dominik