RSA_meth_set_finish
if (RSA_meth_set_finish(new_method, p11_rsa_finish) != 1)
!RSA_meth_set_finish(rsa_meth, rsa_finish))
|| !RSA_meth_set_finish(capi_rsa_method, capi_rsa_free)
int RSA_meth_set_finish(RSA_METHOD *rsa, int (*finish)(RSA *rsa));