Remove extraneous "while(0)".

Oops.

cmr=v1.7.5:ticket=trac:4395

This commit was SVN r31075.

The following Trac tickets were found above:
  Ticket 4395 --> https://svn.open-mpi.org/trac/ompi/ticket/4395

ompi/mca/coll/ml/coll_ml_module.c

@@ -2502,7 +2502,7 @@ static int mca_coll_ml_fill_in_route_tab(mca_coll_ml_topology_t *topo, ompi_comm
 
         ML_VERBOSE(10, ("\nThe table is:\n============\n%s\n", buff));
         free(buff);
-    } while(0);
+    }
 #endif
 
     for (level = 0; level < topo->n_levels; ++level) {