This PR fix issue in this scenario:
```
in terminal 1:
~# cd /sys/fs/cgroup/cpuset
~# mkdir test
~# cd test
~# cat cpuset.cpus
0-3
~# echo 1 > cpuset.cpu_exclusive (make sure you don't have other cgroups under root)
in terminal 2:
~# echo $$ > /sys/fs/cgroup/cpuset/test/tasks
// set resources.cpu.cpus="0-2" in config.json
~# runc run test1
back to terminal 1:
~# cd test1
~# cat cpuset.cpus
0-2
~# echo 1 > cpuset.cpu_exclusive
in terminal 3:
~# echo $$ > /sys/fs/cgroup/test/tasks
// set resources.cpu.cpus="3" in config.json
~# runc run test2
container_linux.go:247: starting container process caused "process_linux.go:258:
applying cgroup configuration for process caused \"failed to write 0-3\\n to
cpuset.cpus: write /sys/fs/cgroup/cpuset/test2/cpuset.cpus: invalid argument\""
```
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>