Another fix for stack_pref

wo/cli/plugins/stack_pref.py

@@ -1,22 +1,16 @@
 import codecs
 import configparser
 import os
-import pwd
 import random
 import shutil
 import string
-import re
 import requests
 
-import psutil
 from wo.cli.plugins.site_functions import *
-from wo.cli.plugins.sitedb import *
 from wo.cli.plugins.stack_services import WOStackStatusController
-from wo.core.addswap import WOSwap
 from wo.core.apt_repo import WORepo
 from wo.core.aptget import WOAptGet
 from wo.core.cron import WOCron
-from wo.core.download import WODownload
 from wo.core.extract import WOExtract
 from wo.core.fileutils import WOFileUtils
 from wo.core.git import WOGit