BibSched: fixes ABOUT-TO-SLEEP scheduling bug

* Fixes a scheduling bug occuring when a task is in "ABOUT TO SLEEP".
  It would previously try to sleep a task in about-to-sleep status
  over and over again.  (fixes #1078)

modules/bibsched/lib/bibsched.py

@@ -1024,7 +1024,8 @@ def get_tasks_to_sleep_and_stop(self, proc, task_set):
         for (this_task_id, this_proc, this_priority, this_status, this_sequenceid) in task_set:
             if not self.is_task_safe_to_execute(this_proc, proc):
                 to_stop.append((this_task_id, this_proc, this_priority, this_status, this_sequenceid))
-            elif (min_prio is None or this_priority < min_prio) and this_status != 'SLEEPING':
+            elif (min_prio is None or this_priority < min_prio) and \
+                            this_status not in ('SLEEPING', 'ABOUT TO SLEEP'):
                 ## We don't put to sleep already sleeping task :-)
                 min_prio = this_priority
                 min_task_id = this_task_id