Tidy.

src/data/sparse_page_dmatrix.cc

@@ -73,7 +73,7 @@ void SparsePageDMatrix::InitializeSparsePage() {
   DMatrixProxy *proxy = MakeProxy(proxy_);
   sparse_page_source_.reset();  // clear before creating new one to prevent conflicts.
   sparse_page_source_ = std::make_shared<SparsePageSource>(
-      iter, proxy, this->missing_, this->nthreads_, this->Info().num_col_,
+      iter, proxy, this->missing_, this->nthreads_, this->info_.num_col_,
       this->n_batches_, cache_info_.at(id));
 }