The code was creating a new instance of vtkOverlappingAMR everytime
RequestInformation was called which would then ShallowCopy() the
metadata coming from upstream. This could lead to creation of multiple
instance of vtkOverlappingAMR that are not properly deallocated and
hence lead to leaks. Instead, the code does not allocate a new instance
but, simply updates the point to point to the metadata object coming from
upstream.

Change-Id: I244a4e3c9c57237fa99042d9bc11f229a8aa9d5c