Make plugins not activatable under windows(dbus support needed)

mpris2_support/mpris2_support.py

@@ -1,6 +1,8 @@
 # -*- coding: utf-8 -*-
 
 
+import os
+
 from common import gajim
 from plugins import GajimPlugin
 from plugins.helpers import log_calls
@@ -24,6 +26,9 @@ class Mpris2Plugin(GajimPlugin):
         self.config_dialog = None
         self.artist = self.title = self.source = ''
         self.listener = MusicTrackListener().get()
+        if os.name == 'nt':
+            self.available_text = _('Plugin can\'t be run under Windows.')
+            self.activatable = False
 
     @log_calls('NowListenPlugin')
     def activate(self):