Correctly skip the "mpirun" node when launching orted on it

Mark the node as "unusable" so it does not get included when computing
number of procs for the case where the user does not specify -np.

Signed-off-by: Ralph Castain <rhc@pmix.org>

orte/mca/ras/base/ras_base_node.c

@@ -11,7 +11,7 @@
  *                         All rights reserved.
  * Copyright (c) 2011-2017 Los Alamos National Security, LLC.  All rights
  *                         reserved.
- * Copyright (c) 2014-2018 Intel, Inc.  All rights reserved.
+ * Copyright (c) 2014-2020 Intel, Inc.  All rights reserved.
  * Copyright (c) 2015-2018 Research Organization for Information Science
  *                         and Technology (RIST). All rights reserved.
  * $COPYRIGHT$
@@ -98,6 +98,7 @@ int orte_ras_base_node_insert(opal_list_t* nodes, orte_job_t *jdata)
                 hnp_node->name = strdup("mpirun");
                 skiphnp = true;
                 ORTE_SET_MAPPING_DIRECTIVE(orte_rmaps_base.mapping, ORTE_MAPPING_NO_USE_LOCAL);
+                ORTE_FLAG_SET(hnp_node, ORTE_NODE_NON_USABLE);  // leave this node out of mapping operations
             }
         }
     }

orte/mca/rmaps/base/rmaps_base_support_fns.c

@@ -12,7 +12,7 @@
  * Copyright (c) 2011      Cisco Systems, Inc.  All rights reserved.
  * Copyright (c) 2011-2012 Los Alamos National Security, LLC.
  *                         All rights reserved.
- * Copyright (c) 2014-2018 Intel, Inc. All rights reserved.
+ * Copyright (c) 2014-2020 Intel, Inc.  All rights reserved.
  * Copyright (c) 2016      IBM Corporation.  All rights reserved.
  * $COPYRIGHT$
  *
@@ -314,11 +314,15 @@ int orte_rmaps_base_get_target_nodes(opal_list_t *allocated_nodes, orte_std_cntr
         /* the list is empty - if the HNP is allocated, then add it */
         if (orte_hnp_is_allocated) {
             nd = (orte_node_t*)opal_pointer_array_get_item(orte_node_pool, 0);
+            if (!ORTE_FLAG_TEST(nd, ORTE_NODE_NON_USABLE)) {
                 OBJ_RETAIN(nd);
                 opal_list_append(allocated_nodes, &nd->super);
             } else {
                 nd = NULL;
             }
+        } else {
+            nd = NULL;
+        }
     } else {
         nd = (orte_node_t*)opal_list_get_last(allocated_nodes);
     }