Utils cgroup

Fix a bug in the regexp in the ```get_cgroup_mountpoint()``` function as it takes also the " cgroup" part from:

```
cgroup /sys/fs/cgroup/cpuset cgroup rw,nosuid,nodev,noexec,relatime,cpuset 0 0
```

Before this patch you will get ```/sys/fs/cgroup/cpuset cgroup``` and after this patch you will get ```/sys/fs/cgroup/cpuset```

I've also included a patch by Hao-Liu, but without his modification on how to parse the cgroup mounts, because it won't work with older cgroup mounts:

```
cgroup on /sys/fs/cgroup/cpuset type cgroup rw,nosuid,nodev,noexec,relatime,cpuset 0 0
```