Cast int to string

Fix  #224

jlmkr.py

@@ -1306,7 +1306,7 @@ def create_jail(**kwargs):
             value = kwargs.pop(option)
             if (
                 value is not None
-                and len(value)
+                and len(str(value))
                 and value is not config.my_get(option, None)
             ):
                 # TODO: this will wipe all systemd_nspawn_user_args from the template...