Change periodic schedule strategy from last_started to last_finished
diff --git a/staffeln/conductor/backup.py b/staffeln/conductor/backup.py
index 1b83409..69c48f4 100755
--- a/staffeln/conductor/backup.py
+++ b/staffeln/conductor/backup.py
@@ -132,7 +132,6 @@
                 queue.backup_status = constants.BACKUP_WIP

                 queue.save()

             except exceptions as error:

-                print("catch error")

                 print(error)

         else:

             pass

diff --git a/staffeln/conductor/manager.py b/staffeln/conductor/manager.py
index fc00d6b..78869e0 100755
--- a/staffeln/conductor/manager.py
+++ b/staffeln/conductor/manager.py
@@ -30,7 +30,7 @@
         periodic_callables = [
             (self.backup_engine, (), {}),
         ]
-        periodic_worker = periodics.PeriodicWorker(periodic_callables)
+        periodic_worker = periodics.PeriodicWorker(periodic_callables, schedule_strategy="last_finished")
         periodic_thread = threading.Thread(target=periodic_worker.start)
         periodic_thread.daemon = True
         periodic_thread.start()
@@ -98,7 +98,7 @@
         periodic_callables = [
             (self.rotation_engine, (), {}),
         ]
-        periodic_worker = periodics.PeriodicWorker(periodic_callables)
+        periodic_worker = periodics.PeriodicWorker(periodic_callables, schedule_strategy="last_finished")
         periodic_thread = threading.Thread(target=periodic_worker.start)
         periodic_thread.daemon = True
         periodic_thread.start()