STYLE: prefer autoPtr::reset() to autoPtr::set()

- in most cases already checked valid() so don't need additional check
  for setting an existing pointer

applications/utilities/mesh/advanced/collapseEdges/collapseEdges.C

@@ -166,7 +166,7 @@ int main(int argc, char *argv[])
 
 
         {
-            meshFilterPtr.set
+            meshFilterPtr.reset
             (
                 new polyMeshFilter(mesh, pointPriority, collapseDict)
             );