Fix more unused parameter warnings (#1076)

src/fix_ave_time.cpp

@@ -529,7 +529,7 @@ void FixAveTime::init()
    only does something if nvalid = current timestep
 ------------------------------------------------------------------------- */
 
-void FixAveTime::setup(int vflag)
+void FixAveTime::setup(int /*vflag*/)
 {
   end_of_step();
 }