Added Catamount to the conditional compilation since Catamount

doesn't support fork() or pipe() either.  This removes a
linker warning message when building for Cray XT with Catamount.

This commit was SVN r16772.

orte/mca/sds/base/sds_base_universe.c

@@ -228,7 +228,7 @@ orte_sds_base_seed_set_name(void)
 
 static int fork_hnp(void)
 {
-#if !defined(__WINDOWS__)
+#if !defined(__WINDOWS__) && !defined(__LIBCATAMOUNT__)
     int p[2], death_pipe[2];
     char *cmd;
     char **argv = NULL;