RPC cfx_estimateGasAndCollateral should return storage limit that won't fail

[boqiu]

Sometimes, the cfx_estimateGasAndCollateral returned storage limit is not enough for the transaction execution. Per @ChenxingLi , it's an EVM issue that required storage is estimation * 64 / 63

[Pana]

This RPC method seems has another issue, when a contract deploy transaction send, if the from field specified(nonce not specified) it will return an address conflict error, seems it use a default nonce 0, i think should use account's current nonce