Register the singleton's nspace with the PMIx server

Once we have created the necessary PRRTE infrastructure
to support the singleton, we need to register that info
with our internal PMIx server so it can be served to
any requesting clients.

Signed-off-by: Ralph Castain <rhc@pmix.org>
(cherry picked from commit 89fdffe)

Author: rhc54

src/tools/prte/prte.c

@@ -104,6 +104,7 @@
 #include "src/runtime/runtime.h"
 
 #include "include/prte.h"
+#include "src/prted/pmix/pmix_server.h"
 #include "src/prted/pmix/pmix_server_internal.h"
 #include "src/prted/prted.h"
 
@@ -1438,7 +1439,10 @@ static int prep_singleton(const char *name)
     node->num_procs = 1;
     node->slots_inuse = 1;
 
-    return PRTE_SUCCESS;
+    // register the info with our PMIx server
+    rc = prte_pmix_server_register_nspace(jdata);
+
+    return rc;
 }
 
 static void signal_forward_callback(int signum, short args, void *cbdata)