plugin_installer. fix self update

plugin_installer/config_dialog.ui

@@ -264,7 +264,7 @@
   </object>
   <object class="GtkWindow" id="window2">
     <child>
-      <object class="GtkVBox" id="vbox11">
+      <object class="GtkVBox" id="hbox111">
         <property name="visible">True</property>
         <property name="orientation">vertical</property>
         <child>

plugin_installer/plugin_installer.py

@@ -537,8 +537,8 @@ class PluginInstallerPluginConfigDialog(GajimPluginConfigDialog):
             'config_dialog.ui')
         self.xml = gtk.Builder()
         self.xml.set_translation_domain('gajim_plugins')
-        self.xml.add_objects_from_file(self.GTK_BUILDER_FILE_PATH, ['vbox11'])
-        hbox = self.xml.get_object('vbox11')
+        self.xml.add_objects_from_file(self.GTK_BUILDER_FILE_PATH, ['hbox111'])
+        hbox = self.xml.get_object('hbox111')
         self.child.pack_start(hbox)
 
         self.xml.connect_signals(self)