message: remove StakeKeyInfo
diff: @@ -4,12 +4,6 @@ use chain_core::mempack::{ReadBuf, ReadError, Readable};
  use chain_core::property;
  use chain_crypto::{Ed25519, PublicKey};
  -/// Information related to a stake key
  -#[derive(Debug, Clone, PartialEq, Eq)]
  -pub struct StakeKeyInfo {
  - pub(crate) pool: Option<StakePoolId>,
  -}
  -
  #[derive(Debug, Clone, PartialEq, Eq, Hash, PartialOrd, Ord)]
  pub struct StakePoolId(Hash);
  