* Store the cert in the SocketData.
* Store the cert and slot in the SocketData.
Java_org_mozilla_jss_ssl_SocketBase_setClientCert(    JNIEnv *env, jobject self, jobject certObj){    JSSL_SocketData *sock = NULL;    SECStatus status;    CERTCertificate *cert = NULL;    if( certObj == NULL ) {        JSS_throw(env, NULL_POINTER_EXCEPTION);        goto finish;    }    if( JSSL_getSockData(env, self, &sock) != PR_SUCCESS) goto finish;    /*     * Store the cert in the SocketData.     */    if( JSS_PK11_getCertPtr(env, certObj, &cert) != PR_SUCCESS ) {        goto finish;    }    if( sock->clientCert != NULL ) {        CERT_DestroyCertificate(sock->clientCert);    }    sock->clientCert = CERT_DupCertificate(cert);    /*     * Install the callback.     */    status = SSL_GetClientAuthDataHook(sock->fd, JSSL_GetClientAuthData,                    (void*)sock);    if(status != SECSuccess) {        JSSL_throwSSLSocketException(env,            "Unable to set client auth data hook");        goto finish;    }finish:    EXCEPTION_CHECK(env, sock)}