message: do not expect the coin value by default
diff: @@ -906,7 +906,7 @@ fn transaction_commands_definition<'a, 'b>() -> App<'a, 'b> {
  .about("Add an input to a transaction")
  .arg(transaction_argument_name_definition())
  .arg(transaction_argument_txid_definition())
  - .arg(transaction_argument_index_definition().requires("TRANSACTION_AMOUNT"))
  + .arg(transaction_argument_index_definition())
  .arg(transaction_argument_amount_definition())
  )
  .subcommand(SubCommand::with_name(TransactionCmd::AddOutput.as_string())
  