message: Pass export privkey DER compression flag correctly
  By passing a bitfield where a boolean was expected, the result was
  always compressed. Fix this.
diff: @@ -89,7 +89,7 @@ static int ec_privkey_import_der(const secp256k1_context* ctx, unsigned char *ou
  * will be set to the number of bytes used in the buffer.
  * key32 must point to a 32-byte raw private key.
  */
  -static int ec_privkey_export_der(const secp256k1_context *ctx, unsigned char *privkey, size_t *privkeylen, const unsigned char *key32, int compressed) {
  +static int ec_privkey_export_der(const secp256k1_context *ctx, unsigned char *privkey, size_t *privkeylen, const unsigned char *key32, bool compressed) {
  assert(*privkeylen >= CKey::PRIVATE_KEY_SIZE);
  secp256k1_pubkey pubkey;
  size_t pubkeylen = 0;
  @@ -170,7 +170,7 @@ CPrivKey CKey::GetPrivKey() const {
  size_t privkeylen;
  privkey.resize(PRIVATE_KEY_SIZE);
  privkeylen = PRIVATE_KEY_SIZE;
  - ret = ec_privkey_export_der(secp256k1_context_sign, privkey.data(), &privkeylen, begin(), fCompressed ? SECP256K1_EC_COMPRESSED : SECP256K1_EC_UNCOMPRESSED);
  + ret = ec_privkey_export_der(secp256k1_context_sign, privkey.data(), &privkeylen, begin(), fCompressed);
  assert(ret);
  privkey.resize(privkeylen);
  return privkey;
  