Use PKeyRef in X509Generator

use bio::{MemBio, MemBioSlice};

use crypto::CryptoString;

use hash::MessageDigest;

use pkey::PKey;

use pkey::{PKey, PKeyRef};

use rand::rand_bytes;

use error::ErrorStack;

use ffi;

    }

    /// Sets the certificate public-key, then self-sign and return it

    pub fn sign(&self, p_key: &PKey) -> Result<X509, ErrorStack> {

    pub fn sign(&self, p_key: &PKeyRef) -> Result<X509, ErrorStack> {

        ffi::init();

        unsafe {

    }

    /// Obtain a certificate signing request (CSR)

    pub fn request(&self, p_key: &PKey) -> Result<X509Req, ErrorStack> {

    pub fn request(&self, p_key: &PKeyRef) -> Result<X509Req, ErrorStack> {

        let cert = match self.sign(p_key) {

            Ok(c) => c,

            Err(x) => return Err(x),