Fix the grouping code when some objects are not...
Fix the grouping code when some objects are not...

Fix the grouping code when some objects are not placed in any group

Thanks to Bernd Kallies for the report and the patch (very slightly reworked by me)

This commit was SVN r3164.

ggouaillardet/hwloc,shekkbuilder/hwloc,shekkbuilder/hwloc,shekkbuilder/hwloc,ggouaillardet/hwloc,ggouaillardet/hwloc,shekkbuilder/hwloc,ggouaillardet/hwloc