Permanent leasehold estates, renewable forever, shall be considered to be estates in fee simple, and shall be subject to the same modes of alienation, power of devise, and rules of descent and distribution, and to all the incidents of an estate in fee, provided that the grantor of the leasehold or the person entitled to the estate, out of which the term issues, has first released to the grantee of the term or the person in possession of the leasehold all his right to the rent charged upon or growing out of the leasehold.