test_pluginmanager: fix imports

test/test_pluginmanager.py

@@ -38,8 +38,8 @@ configdir = gajim_root + '/test/tmp'
 import time
 
 # define _ for i18n
-import __builtin__
-__builtin__._ = lambda x: x
+import builtins
+builtins._ = lambda x: x
 
 # wipe config directory
 import os
@@ -54,7 +54,6 @@ gajim.common.configpaths.gajimpaths.init(configdir)
 
 # for some reason common.app needs to be imported before xmpppy?
 from gajim.common import app
-from gajim.common import xmpp
 
 app.DATA_DIR = gajim_root + '/data'