Optimization: check if msg.value == 0 forces a storage cell re-write

[SergioDemianLerner]

Storage cell writes are very expensive in RSK. If msg.value is zero this write would be unnecessary. Check that Solidity performs the zero check or not (by disassembling or by executing with zero msg.value and checking gas usage).

liquidity-bridge-contract/contracts/LiquidityBridgeContract.sol

Line 59 in 03184a1

balances[params.liquidityProviderRskAddress] += msg.value;