Quiet a warning on the Cray systems in which mkfifo does not work.

Thanks to Lisa Glendenning for mentioning this, and Brian for following
up with me on it.

This commit was SVN r15392.

opal/runtime/opal_cr.c

@@ -595,6 +595,9 @@ static int cr_notify_reopen_files(int *prog_read_fd, int *prog_write_fd)
 {
     int ret = OPAL_ERR_NOT_IMPLEMENTED;
 
+#ifndef HAVE_MKFIFO
+    return ret;
+#else
 #ifdef __WINDOWS__
     return ret;
 #else
@@ -650,6 +653,7 @@ static int cr_notify_reopen_files(int *prog_read_fd, int *prog_write_fd)
     
     return OPAL_SUCCESS;
 #endif  /* __WINDOWS__ */
+#endif  /* HAVE_MKFIFO */
 }
 
 /*