Remove redundancy statement on iost.transfer

[nujabes403]

let t = this.callABI("token.iost", "transfer", [token, from, to, amount, memo]);

In above statement, this.callABI already do t.addApprove("*", this.config.defaultLimit); internally.

So there is no reason to set defaultGasLimit twice when call transfer.

cf)

1. callABI function

    callABI(contract, abi, args) {
        const t = new Tx(this.config.gasRatio, this.config.gasLimit);
        t.addAction(contract, abi, JSON.stringify(args));
        t.setTime(this.config.expiration, this.config.delay);
        t.addApprove("*", this.config.defaultLimit); // already approve defaultLimit!
        return t
    }

2. transfer function

    transfer(token, from, to, amount, memo = "") {
        let t = this.callABI("token.iost", "transfer", [token, from, to, amount, memo]);
        t.addApprove("*", this.config.defaultLimit); // redundant!
        t.addApprove("iost", amount); 
        return t;
    }