FileIO: (linux) fix compile use URL instead of NSURL
FileIO: (linux) fix compile use URL instead of NSURL

cburrows/swift-protobuf,cburrows/swift-protobuf,thomasvl/swift-protobuf,allevato/swift-protobuf,apple/swift-protobuf,allevato/swift-protobuf,thomasvl/swift-protobuf,thomasvl/swift-protobuf,thomasvl/swift-protobuf,apple/swift-protobuf,thomasvl/swift-protobuf,tbkka/swift-protobuf,allevato/swift-protobuf,allevato/swift-protobuf,allevato/swift-protobuf,cburrows/swift-protobuf,cburrows/swift-protobuf,apple/swift-protobuf,cburrows/swift-protobuf,thomasvl/swift-protobuf,apple/swift-protobuf,cburrows/swift-protobuf,thomasvl/swift-protobuf,allevato/swift-protobuf,apple/swift-protobuf,allevato/swift-protobuf,apple/swift-protobuf,tbkka/swift-protobuf,tbkka/swift-protobuf,tbkka/swift-protobuf,apple/swift-protobuf,tbkka/swift-protobuf,cburrows/swift-protobuf,tbkka/swift-protobuf,tbkka/swift-protobuf