Merge pull request #1595 from hjelmn/sparse_group_fix

ompi/group: fix sparse group proc reference counting

ompi/group/group_init.c

@@ -275,7 +275,11 @@ static void ompi_group_destruct(ompi_group_t *group)
        the proc counts are not increased during the constructor,
        either). */
 
-    ompi_group_decrement_proc_count (group);
+#if OMPI_GROUP_SPARSE
+    if (OMPI_GROUP_IS_DENSE(group))
+	/* sparse groups do not increment proc reference counters */
+#endif
+	ompi_group_decrement_proc_count (group);
 
     /* release thegrp_proc_pointers memory */
     if (NULL != group->grp_proc_pointers) {