Revert "vtkGenericIOUtilities: use std::function over std::ptr_fun"

This reverts commit 8bbdf406a46a7613b38ae068e2cb81832f8d33a6.

Change-Id: Ibe3c65be029914fb80360f859ceb7418b9d537dd
Merge topic 'include-missing-header' into next

3ad343f7 Revert "vtkGenericIOUtilities: use std::function over std::ptr_fun"