message: [Operational Management] Fix bug in set_validator: fetch seq number from operator account.
  Closes:
  Approved by: gregnazario
diff: use crate::{json_rpc::JsonRpcClientWrapper, TransactionContext};
  use libra_crypto::{ed25519::Ed25519PublicKey, x25519};
  use libra_global_constants::{
  - CONSENSUS_KEY, FULLNODE_NETWORK_KEY, OWNER_ACCOUNT, VALIDATOR_NETWORK_KEY,
  + CONSENSUS_KEY, FULLNODE_NETWORK_KEY, OPERATOR_ACCOUNT, OWNER_ACCOUNT, VALIDATOR_NETWORK_KEY,
  };
  use libra_management::{
  error::Error,
  @@ -37,10 +37,11 @@ impl SetValidatorConfig {
  self.validator_config.validator_backend.name(),
  &self.validator_config.validator_backend.validator_backend,
  )?;
  + let operator_account = storage.account_address(OPERATOR_ACCOUNT)?;
  let owner_account = storage.account_address(OWNER_ACCOUNT)?;
  let client = JsonRpcClientWrapper::new(self.host);
  - let sequence_number = client.sequence_number(owner_account)?;
  + let sequence_number = client.sequence_number(operator_account)?;
  // Retrieve the current validator / fullnode addresses and update accordingly
  let validator_config = client.validator_config(owner_account)?;
  