Fix a potential NULL reference

This commit was SVN r21127.

opal/tools/opal-restart/opal-restart.c

@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2004-2008 The Trustees of Indiana University and Indiana
+ * Copyright (c) 2004-2009 The Trustees of Indiana University and Indiana
  *                         University Research and Technology
  *                         Corporation.  All rights reserved.
  * Copyright (c) 2004-2005 The University of Tennessee and The University
@@ -225,7 +225,8 @@ main(int argc, char *argv[])
     /*
      * Make sure we have selected the proper component
      */
-    if(0 != strncmp(expected_crs_comp, 
+    if(NULL == expected_crs_comp ||
+       0 != strncmp(expected_crs_comp, 
                     opal_crs_base_selected_component.base_version.mca_component_name, 
                     strlen(expected_crs_comp)) ) {
         opal_show_help("help-opal-restart.txt", "comp_select_mismatch",