libvirt-test: numatune: Fix some bugs

* VM XML omit numa entry when the placement is auto and mode is strict.
  So we need to set numa_params manually when exception happens.

* Fix typo in cfg file which causes duplicated test name. s/config/live/

* Fix typo. s/KeyError()/KeyError/

* Move restoration of cgroup to finally section to make sure cgroup can
  be restored even when exception happens.

Signed-off-by: Hao Liu <hliu@redhat.com>