Ticket 49532 - coverity issues - fix compiler warnings & clang issues

Description:  Fixed all the warnings

https://pagure.io/389-ds-base/issue/49532

Reviewed by: tbordaz(Thanks!)

ldap/servers/slapd/back-ldbm/idl_set.c

@@ -270,7 +270,7 @@ idl_set_union(IDListSet *idl_set, backend *be)
      * Allocate a new set based on the size of our sets.
      */
     IDList *result_list = idl_alloc(idl_set->total_size);
-    IDList *idl = idl_set->head;
+    IDList *idl = NULL;
     IDList *idl_del = NULL;
     IDList *prev_idl = NULL;
     NIDS last_min = 0;
@@ -398,7 +398,7 @@ idl_set_intersect(IDListSet *idl_set, backend *be)
          * we don't care if we have allids here, because we'll ignore it anyway.
          */
         result_list = idl_alloc(idl_set->minimum->b_nids);
-        IDList *idl = idl_set->head;
+        IDList *idl = NULL;
 
         /* The previous value we inserted. */
         NIDS last_min = 0;

ldap/servers/slapd/control.c

@@ -337,7 +337,7 @@ get_ldapmessage_controls_ext(
         slapi_pblock_set(pb, SLAPI_MANAGEDSAIT, &ctrl_not_found);
         slapi_pblock_set(pb, SLAPI_PWPOLICY, &ctrl_not_found);
         slapi_log_err(SLAPI_LOG_CONNS, "get_ldapmessage_controls_ext", "Warning: conn=%" PRIu64 " op=%d contains an empty list of controls\n",
-                      pb_conn->c_connid, pb_op->o_opid);
+                      pb_conn ? pb_conn->c_connid : -1, pb_op ? pb_op->o_opid : -1);
     } else {
         /* len, ber_len_t is uint, not int, cannot be != -1, may be better to remove this check.  */
         if ((tag != LBER_END_OF_SEQORSET) && (len != -1)) {

src/nunc-stans/ns/ns_thrpool.c

@@ -1587,7 +1587,12 @@ ns_thrpool_shutdown(struct ns_thrpool_t *tp)
      */
     for (size_t i = 0; i < tp->thread_count; i++) {
         ns_result_t result = ns_add_shutdown_job(tp);
-        PR_ASSERT(result == NS_SUCCESS);
+        if (result != NS_SUCCESS) {
+#ifdef DEBUG
+            ns_log(LOG_DEBUG, "ns_thrpool_shutdown - Failed to add shutdown job: error (%d)\n", result);
+#endif
+            PR_ASSERT(0);
+        }
     }
     /* Make sure all threads are woken up to their shutdown jobs. */
     pthread_mutex_lock(&(tp->work_q_lock));