noextra option for write_data

src/write_data.h

@@ -35,6 +35,7 @@ class WriteData : protected Pointers {
   int me,nprocs;
   int pairflag;
   int coeffflag;
+  int extraflag;
   FILE *fp;
   bigint nbonds_local,nbonds;
   bigint nangles_local,nangles;