setFreezer: explicitly return nil

errors.Wrap(err, "some error") returns nil if err is nil, so it's
slightly clearer to just return early than to set the error to nil
and call errors.Wrap(). This is also somewhat defensive in case
we decide to replace `errors.Wrap()` for golang's native `%w`
wrapping.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

libcontainer/cgroups/fs2/freezer.go

@@ -19,7 +19,7 @@ func setFreezer(dirPath string, state configs.FreezerState) error {
 		// freeze the container (since without the freezer cgroup, that's a
 		// no-op).
 		if state == configs.Undefined || state == configs.Thawed {
-			err = nil
+			return nil
 		}
 		return errors.Wrap(err, "freezer not supported")
 	}