Merge pull request #472 from crosbymichael/fix-cgroup-error-handling

path now returns the IsNotFound error

cgroups/fs/apply_raw.go

@@ -99,12 +99,11 @@ func (m *Manager) Apply(pid int) error {
 		// created then join consists of writing the process pids to cgroup.procs
 		p, err := d.path(name)
 		if err != nil {
-			return err
-		}
-		if !cgroups.PathExists(p) {
+			if cgroups.IsNotFound(err) {
 				continue
 			}
-
+			return err
+		}
 		paths[name] = p
 	}
 	m.Paths = paths