update PluginsTranslationsPlugin to py3

plugins_translations/__init__.py

-from plugins_translations import PluginsTranslationsPlugin
+from .plugins_translations import PluginsTranslationsPlugin

plugins_translations/manifest.ini

@@ -5,4 +5,4 @@ version: 0.6.3
 description: This plugin contains translation files for Gajim plugins
 authors = Denis Fomin <fominde@gmail.com>
 homepage = http://trac-plugins.gajim.org/wiki/PluginsTranslationsPlugin
-max_gajim_version: 0.15.9
+min_gajim_version: 0.15.10

plugins_translations/plugins_translations.py

 # -*- coding: utf-8 -*-
 ##
 
-import gobject
 import os
 
 from common import gajim