ParseCgroupFile: fix wrong comment about unified hierarchy

ref: fe19473

Signed-off-by: Akihiro Suda <akihiro.suda.cz@hco.ntt.co.jp>

Author: AkihiroSuda

utils.go

@@ -261,9 +261,7 @@ func parseKV(raw string) (string, uint64, error) {
 //   "pids": "/user.slice/user-1000.slice"
 // etc.
 //
-// Note that for cgroup v2 unified hierarchy, there are no per-controller
-// cgroup paths, so the resulting map will have a single element where the key
-// is empty string ("") and the value is the cgroup path the <pid> is in.
+// The resulting map does not have an element for cgroup v2 unified hierarchy.
 func ParseCgroupFile(path string) (map[string]string, error) {
 	f, err := os.Open(path)
 	if err != nil {