initialize setflag and cutsq pointers to NULL, so they are not accessed uninitialized by accident

src/pair.cpp

@@ -72,6 +72,9 @@ Pair::Pair(LAMMPS *lmp) : Pointers(lmp)
   single_extra = 0;
   svector = NULL;
 
+  setflag = NULL;
+  cutsq = NULL;
+
   ewaldflag = pppmflag = msmflag = dispersionflag = tip4pflag = dipoleflag = 0;
   reinitflag = 1;