Fixed sessions cron commands

misago/sessions/management/commands/clearsessions.py

@@ -1,3 +1,4 @@
+from datetime import timedelta
 from django.core.exceptions import ValidationError, NON_FIELD_ERRORS
 from django.core.management.base import BaseCommand, CommandError
 from django.utils import timezone

misago/sessions/management/commands/cleartokens.py

@@ -1,3 +1,4 @@
+from datetime import timedelta
 from django.core.exceptions import ValidationError, NON_FIELD_ERRORS
 from django.core.management.base import BaseCommand, CommandError
 from django.utils import timezone