check_disk: Remove unused status variable

We didn't actually use the exit status provided by pthread_join(3) for
anything.

plugins/check_disk.c

@@ -996,7 +996,6 @@ stat_path (struct parameter_list *p)
 {
 #ifdef HAVE_PTHREAD_H
   pthread_t stat_thread;
-  int status;
   int statdone = 0;
   int timer = timeout_interval;
   struct timespec req, rem;
@@ -1014,7 +1013,7 @@ stat_path (struct parameter_list *p)
     }
   }
   if (statdone == 1) {
-    pthread_join(stat_thread, (void *)&status);
+    pthread_join(stat_thread, NULL);
   } else {
     pthread_detach(stat_thread);
     if (verbose >= 3)