UnpackingScheduler: Initialize managers in start

Related #1049

src/scheduler/unpacking_scheduler.py

@@ -44,17 +44,20 @@ def __init__(self, post_unpack=None, analysis_workload=None, fs_organizer=None,
         self.get_analysis_workload = analysis_workload
         self.in_queue = Queue()
         self.work_load_counter = 25
-        self.manager = Manager()
-        self.workers = self.manager.list()  # type: list[ExtractionContainer]
         self.worker_tmp_dirs = []  # type: list[TemporaryDirectory]
         self.pending_tasks: dict[int, Thread] = {}
         self.post_unpack = post_unpack
         self.unpacking_locks = unpacking_locks
         self.unpacker = Unpacker(fs_organizer=fs_organizer, unpacking_locks=unpacking_locks)
+
+        self.manager = None
+        self.workers = None
         self.work_load_process = None
         self.extraction_process = None
 
     def start(self):
+        self.manager = Manager()
+        self.workers = self.manager.list()  # type: list[ExtractionContainer]
         self.create_containers()
         self.work_load_process = self.start_work_load_monitor()
         self.extraction_process = self._start_extraction_loop()