Improve hwloc_drop_useless_io() so that we can reuse it when filtering out I/O after XML import
Improve hwloc_drop_useless_io() so that we can reuse it when filtering out I/O after XML import

It must handle !IO_DEVICES && !WHOLE_IO too (drop everything)

git-svn-id: 14be032f8f42541b1a281b51ae8ea69814daf20e@3931 4b44e086-7f34-40ce-a3bd-00e031736276

BlueBrain/hwloc,BlueBrain/hwloc,BlueBrain/hwloc,BlueBrain/hwloc