initialize boolean (reported by coverity)

src/Statistics.cpp

@@ -33,7 +33,7 @@ void Statistics::update(CursorData const & cur, bool skip)
 {
 	// early exit if the buffer has not changed since last time
 	if (stats_id_ == cur.buffer()->id())
-               return;
+		return;
 
 	// reset counts
 	*this = Statistics();

src/Statistics.h

@@ -55,7 +55,7 @@ private:
 	void update(Paragraph const & par, pos_type from = 0, pos_type to = -1);
 
 	// Indicate whether parts that produce no output should be counted.
-	bool skip_no_output_;
+	bool skip_no_output_ = false;
 	// Used in the code to track status
 	bool inword_ = false;
 	// The buffer id at last statistics computation.