Remove obsolete comment from early file locking implementation

Signed-off-by: Patrick Decat <pdecat@gmail.com>

cmd/helm/repo_add_test.go

@@ -128,7 +128,6 @@ func TestRepoAddConcurrentGoRoutines(t *testing.T) {
 	wg.Add(3)
 	for i := 0; i < 3; i++ {
 		go func(name string) {
-			// TODO: launch repository additions in sub-processes as file locks are bound to processes, not file descriptors
 			defer wg.Done()
 			if err := addRepository(name, ts.URL(), "", "", settings.Home, "", "", "", true); err != nil {
 				t.Error(err)