fix error of timeout when using Truffle to deploy contract

[KamiD]

Closes: #767

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maybe diff impl

[araskachoi]

GetGas() just gives the gas limit correct?
would it be better to use:
gasUsed.Add(gasUsed, ethTx.Fee().Int64())

[KamiD]

I think here need return gas used, not gas fee used, also, the number of Fee() is too big to return to the interface of web3.js, that will be crashed in web3.js lib cause too large number transform

[KamiD]

ethTx.Fee() return gaslimit * gasPrice, its much larger than real number of gas costed