Let management command always run synchronously

aleksis/apps/ldap/management/commands/mass_ldap_import.py

 from django.core.management.base import BaseCommand
 
-from ...tasks import ldap_import
+from ...util.ldap_sync import mass_ldap_import
 
 
 class Command(BaseCommand):
     def handle(self, *args, **options):
-        ldap_import()
+        mass_ldap_import()