Remove confusing comment left from FinalizableCrowdsale
Remove confusing comment left from FinalizableCrowdsale

AFter this PR 
https://github.com/OpenZeppelin/zeppelin-solidity/pull/364
the comment was left.
OpenZeppelin/openzeppelin-contracts,OpenZeppelin/zeppelin-solidity,OpenZeppelin/zep-solidity,OpenZeppelin/zep-solidity,OpenZeppelin/zeppelin-solidity,pash7ka/zeppelin-solidity,dmx374/zeppelin-solidity,OpenZeppelin/openzeppelin-contracts,OpenZeppelin/openzeppelin-contracts,dmx374/zeppelin-solidity,pash7ka/zeppelin-solidity