message: trivial: reuse ensure_slice_len_eq when possible
diff: //! `Version` is serialized in big endian so that records in RocksDB will be in order of it's
  //! numeric value.
  -use crate::schema::TRANSACTION_INFO_CF_NAME;
  -use anyhow::{ensure, Result};
  +use crate::schema::{ensure_slice_len_eq, TRANSACTION_INFO_CF_NAME};
  +use anyhow::Result;
  use byteorder::{BigEndian, ReadBytesExt};
  use libra_types::transaction::{TransactionInfo, Version};
  use schemadb::{
  @@ -35,11 +35,7 @@ impl KeyCodec<TransactionInfoSchema> for Version {
  }
  fn decode_key(data: &[u8]) -> Result<Self> {
  - ensure!(
  - data.len() == size_of::<Version>(),
  - "Bad num of bytes: {}",
  - data.len()
  - );
  + ensure_slice_len_eq(data, size_of::<Version>())?;
  Ok((&data[..]).read_u64::<BigEndian>()?)
  }
  }
  