various fixes for singleton support

some recent changes broke singleton support - twice in a month.

First, remove problematic PMIX_RELEASE of jdata when its not ready to be removed.

For some reason this showed up in singleton mode with debug enabled.
Various asserts would fail when this PMIX_RELEASE was invoked.
This was due to the fact that the jdata had been put on a list of jdata's
so the opal_list destructor was having a fit trying to release a jdata
which was still in a list.

It turns out this jdata is being released in the code starting at
line 95 of prte_finalize.c.   I assume with debug not enabled that the
jdata is released twice, rather than failing in the assert in prted_comm.c

Some work to add in session id's for tracking allocations also broke
singleton support.

This patch restores the singletone functionality.

Related to issue open-mpi/ompi#12307

Signed-off-by: Howard Pritchard <howardp@lanl.gov>

src/mca/plm/base/plm_base_receive.c

@@ -271,7 +271,10 @@ void prte_plm_base_recv(int status, pmix_proc_t *sender,
             /* try defaulting to parent session */
             if (NULL != (parent = prte_get_job_data_object(nptr->nspace))) {
                 session = parent->session;
-
+		if (NULL == session) {
+                    rc = PRTE_ERR_NOT_FOUND;
+                    goto ANSWER_LAUNCH;
+                }
             // (RHC) This next clause merits some thought - not sure I fully
             // understand the conditionals
             } else if (!prte_pmix_server_globals.scheduler_connected ||

src/prted/prted_comm.c

@@ -502,7 +502,6 @@ void prte_daemon_recv(int status, pmix_proc_t *sender,
         PMIX_LOAD_PROCID(&pname, job, PMIX_RANK_WILDCARD);
         prte_pmix_server_clear(&pname);
 
-        PMIX_RELEASE(jdata);
         break;
 
         /****     REPORT TOPOLOGY COMMAND    ****/

src/tools/prte/prte.c

@@ -1401,6 +1401,7 @@ static int prep_singleton(const char *name)
     jdata = PMIX_NEW(prte_job_t);
     PMIX_LOAD_NSPACE(jdata->nspace, ptr);
     free(ptr);
+    jdata->session = prte_default_session;
     rc = prte_set_job_data_object(jdata);
     if (PRTE_SUCCESS != rc) {
         PRTE_UPDATE_EXIT_STATUS(PRTE_ERR_FATAL);