When an insertion occurs in the grouping code, ...
When an insertion occurs in the grouping code, ...

When an insertion occurs in the grouping code, display a different
error message if the distance matrix was given by the user.

This commit was SVN r3213.

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