Shave some time off of mpirun's operation by not waiting for the listener thread to terminate before exiting

cmr=v1.8.1:reviewer=rhc

This commit was SVN r31368.

orte/mca/oob/tcp/oob_tcp_component.c

@@ -660,7 +660,6 @@ static void component_shutdown(void)
 
     if (ORTE_PROC_IS_HNP && mca_oob_tcp_component.listen_thread_active) {
         mca_oob_tcp_component.listen_thread_active = 0;
-        opal_thread_join(&mca_oob_tcp_component.listen_thread, NULL);
     }
 
     while (NULL != (item = opal_list_remove_first(&mca_oob_tcp_component.listeners))) {