Don't double check if the global id has content cache during invalidation

boards/management/commands/invalidate_sync_cache.py

@@ -14,7 +14,7 b' class Command(BaseCommand):'
         count = 0
         for global_id in GlobalId.objects.exclude(content__isnull=True).exclude(
                 content=''):
-            if global_id.is_local() and global_id.content is not None:
+            if global_id.is_local():
                 global_id.content = None
                 global_id.save()
                 global_id.signature_set.all().delete()