cgroups: Add a name cgroup

This is meant to be used in retrieving the paths so an exec
process enters all the cgroup paths correctly.

Signed-off-by: Mrunal Patel <mrunalp@gmail.com>

libcontainer/cgroups/fs/name.go

@@ -0,0 +1,25 @@
+package fs
+
+import (
+	"github.com/opencontainers/runc/libcontainer/cgroups"
+	"github.com/opencontainers/runc/libcontainer/configs"
+)
+
+type NameGroup struct {
+}
+
+func (s *NameGroup) Apply(d *data) error {
+	return nil
+}
+
+func (s *NameGroup) Set(path string, cgroup *configs.Cgroup) error {
+	return nil
+}
+
+func (s *NameGroup) Remove(d *data) error {
+	return nil
+}
+
+func (s *NameGroup) GetStats(path string, stats *cgroups.Stats) error {
+	return nil
+}