[consensus] Do not print stack trace when fetch failed
[consensus] Do not print stack trace when fetch failed

This stack trace is useless and pollutes log

Closes: #1290
Approved by: dmitri-perelman

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