(2) When a person restrained by virtue of a judgment upon a conviction of crime asserts the illegality of the restraint upon grounds other than the unlawfulness of such judgment or the proceedings upon which it is based or in the appellate review thereof, relief shall not be available under ORS 138.510 to 138.680 but shall be sought by habeas corpus or other remedies, if any, as otherwise provided by law. As used in this subsection, such other grounds include but are not limited to unlawful revocation of parole or conditional pardon or completed service of the sentence imposed. [1959 c.636 §4]