mpool: mpi_show_mpi_alloc_mem_leaks don't print out message if there are no leaks

Signed-off-by: Nathan Hjelm <hjelmn@lanl.gov>

opal/mca/mpool/base/mpool_base_tree.c

@@ -182,6 +182,9 @@ void mca_mpool_base_tree_print(int show_up_to_mem_leaks)
     num_leaks = 0;
     max_mem_leaks = show_up_to_mem_leaks;
     opal_rb_tree_traverse(&mca_mpool_base_tree, condition, action);
+    if (0 == num_leaks) {
+        return;
+    }
 
     if (num_leaks <= show_up_to_mem_leaks ||
         show_up_to_mem_leaks < 0) {