btl/scif: remove call to pthread_cancel

There is no reason to cancel the listening thread. It should die
automatically when the file descriptor is closed. It is sufficient
to just wait for the thread to exit with pthread join.

cmr=v1.8.2:ticket=trac:4616:reviewer=jsquyres

This commit was SVN r31738.

The following Trac tickets were found above:
  Ticket 4616 --> https://svn.open-mpi.org/trac/ompi/ticket/4616

ompi/mca/btl/scif/btl_scif_module.c

@@ -125,9 +125,8 @@ mca_btl_scif_module_finalize (struct mca_btl_base_module_t *btl)
 
     /* close the listening endpoint */
     if (-1 != mca_btl_scif_module.scif_fd) {
-        pthread_cancel(mca_btl_scif_module.listen_thread);
-        pthread_join(mca_btl_scif_module.listen_thread, NULL);
         scif_close (mca_btl_scif_module.scif_fd);
+        pthread_join(mca_btl_scif_module.listen_thread, NULL);
     }
 
     mca_btl_scif_module.scif_fd = -1;