Per email on devel list, change the default rank-by to slot unless map-by <obj> is specified, in which case use rank-by <obj>

Refs trac:3977

This commit was SVN r29945.

The following Trac tickets were found above:
  Ticket 3977 --> https://svn.open-mpi.org/trac/ompi/ticket/3977

orte/mca/rmaps/base/rmaps_base_map_job.c

@@ -109,16 +109,9 @@ void orte_rmaps_base_map_job(int fd, short args, void *cbdata)
                 ORTE_SET_MAPPING_POLICY(map->mapping, ORTE_MAPPING_BYSOCKET);
             }
         }
-        if (ORTE_RANKING_GIVEN & ORTE_GET_RANKING_DIRECTIVE(orte_rmaps_base.ranking)) {
+        /* ranking was already handled, so just use it here */
-            map->ranking = orte_rmaps_base.ranking;
+        map->ranking = orte_rmaps_base.ranking;
-        } else {
+
-            /* default based on number of procs */
-            if (nprocs <= 2) {
-                ORTE_SET_RANKING_POLICY(map->ranking, ORTE_RANK_BY_SLOT);
-            } else {
-                ORTE_SET_RANKING_POLICY(map->ranking, ORTE_RANK_BY_SOCKET);
-            }
-        }
 #if OPAL_HAVE_HWLOC
         map->binding = opal_hwloc_binding_policy;
 #endif
@@ -158,12 +151,7 @@ void orte_rmaps_base_map_job(int fd, short args, void *cbdata)
         }
         /* ditto for rank and bind policies */
         if (!ORTE_RANKING_POLICY_IS_SET(jdata->map->ranking)) {
-            /* default based on number of procs */
+            jdata->map->ranking = orte_rmaps_base.ranking;
-            if (nprocs <= 2) {
-                ORTE_SET_RANKING_POLICY(jdata->map->ranking, ORTE_RANK_BY_SLOT);
-            } else {
-                ORTE_SET_RANKING_POLICY(jdata->map->ranking, ORTE_RANK_BY_SOCKET);
-            }
         }
 #if OPAL_HAVE_HWLOC
         if (!OPAL_BINDING_POLICY_IS_SET(jdata->map->binding)) {