fix null sentence pointer in wcclparser

wcclparser/main.cpp

@@ -98,6 +98,7 @@ bool process_line(const std::string& line, Parser& parser)
 	boost::shared_ptr<const Wccl::Value> retVal;
 	boost::shared_ptr<ANTLRParserResultBase> retOp;
 	boost::shared_ptr<Corpus2::Sentence> sentence;
+	sentence.reset(new Corpus2::Sentence);
 	Wccl::SentenceContext sc(sentence);
 
 	try {