Get rid of cpu label error message
Get rid of cpu label error message

Errors like

```
{"component":"virt-handler","level":"error","msg":"failed to set a cpu manager label on host node02","pos":"vm.go:1688","reason":"open /proc/16842/cmdline: no such file or directory","timestamp":"2019-07-15T17:13:25.027192Z"}
```

can not occur anymore because we now explicitly handle disappeard
processes.

kubevirt/kubevirt,davidvossel/kubevirt,kubevirt/kubevirt,kubevirt/kubevirt,stu-gott/kubevirt,davidvossel/kubevirt,davidvossel/kubevirt,kubevirt/kubevirt,davidvossel/kubevirt,stu-gott/kubevirt,stu-gott/kubevirt,stu-gott/kubevirt