btl/vader: create the shared memory backing file in the proc's session

directory not the job's

This bug didn't affect the correctness of the vader results just the
cleanup. This commit removes an error message about removing a non-existent
file.

cmr=v1.8:reviewer=jsquyres

This commit was SVN r31265.

ompi/mca/btl/vader/btl_vader_component.c

@@ -297,7 +297,7 @@ static mca_btl_base_module_t **mca_btl_vader_component_init (int *num_btls,
     {
         char *sm_file;
 
-        rc = asprintf(&sm_file, "%s" OPAL_PATH_SEP "vader_segment.%s.%d", ompi_process_info.job_session_dir,
+        rc = asprintf(&sm_file, "%s" OPAL_PATH_SEP "vader_segment.%s.%d", ompi_process_info.proc_session_dir,
                       ompi_process_info.nodename, MCA_BTL_VADER_LOCAL_RANK);
         if (0 > rc) {
             free (btls);