[consensus] Add better expect message
[consensus] Add better expect message

The message right above it says the exact same thing

Closes: #1916
Approved by: davidiw

aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,aptos-labs/aptos-core,libra/libra,aptos-labs/aptos-core,libra/libra,libra/libra