fixed natspec evaluator result on error
fixed natspec evaluator result on error

chriseth/solidity-doc-test,ruchevits/solidity,chriseth/solidity,ruchevits/solidity,gluk256/solidity,ruchevits/solidity,arkpar/solidity,douglas-larocca/solidity,vaporry/solidity,ruchevits/solidity,LianaHus/solidity,debris/solidity,shahankhatch/solidity,ethers/solidity