message: bft leader should preferentially use an secret key although should accept both
diff: @@ -4,7 +4,7 @@ use crate::{
  ledger::{Ledger, LedgerParameters},
  stake::StakePoolId,
  };
  -use chain_crypto::{Curve25519_2HashDH, Ed25519Extended, SecretKey, SumEd25519_12};
  +use chain_crypto::{Curve25519_2HashDH, Ed25519, SecretKey, SumEd25519_12};
  use chain_time::era::TimeEra;
  pub mod bft;
  @@ -44,7 +44,7 @@ macro_rules! try_check {
  }
  pub struct BftLeader {
  - pub sig_key: SecretKey<Ed25519Extended>,
  + pub sig_key: SecretKey<Ed25519>,
  }
  pub struct GenesisLeader {
  