* For now, only "cpu_time" is supported.
* cpuacct cgroup is used for providing percpu cputime information.

* src/qemu/qemu.conf     - take care of cpuacct cgroup.
* src/qemu/qemu_conf.c   - take care of cpuacct cgroup.
* src/qemu/qemu_driver.c - added an interface
* src/util/cgroup.c/h    - added interface for getting percpu cputime
Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NLai Jiangshan <laijs@cn.fujitsu.com>