[config] use the right peer_id for seed_peers
[config] use the right peer_id for seed_peers

Was using the wrong first_peer_id and the test wasn't thorough enough to
find this bug...

Closes: #2011
Approved by: andll

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