Overriding gas estimation seems incorrect

[agazso]

Summary

You should be able to validate this by overriding the gas estimation via passing the --swap-deployment-gas-price string flag upon node startup. However, upon inspection of the code, it seems that this flag is not correctly used.

The flag is read at InitCheckBookService, settlement/swap/chequebook/init.go (ln 177), but in the function checkBalance, settlement/swap/chequebook/init.go, we estimate the gas price even though the user passed in the gas price (ln 51 and 56). This should be reconciled by validating if the gas price was already set and if this is the case, don't read the gas price anymore.

See the original issue description here: #2860