fix(scheduleimport): annother approace to reduce mapping inconsistency #653

This partly reverts commit 63a25241.

src/core/models/schedules.py

@@ -348,6 +348,9 @@ class ScheduleSource(models.Model):
                 )
                 logging.exception('Import on ScheduleSource %s encountered exception on creating mapping for %s "%s".', self.pk, item_type, item_source_id)
 
+                # ... and delete the incomplete (wrong) mapping if it was created
+                if new_mapping:
+                    mapping.delete()
                 return 'error'
 
             else: