[meld] melddoc: Tidy up our UI-merging member variables on switch better

[Kai Willadsen <kaiw src gnome org>]

commit 46b5f3923e4765dea4012bc7b467862e60f1f1c0
Author: Kai Willadsen <kai willadsen gmail com>
Date:   Sun Dec 13 07:11:50 2015 +1000

    melddoc: Tidy up our UI-merging member variables on switch better

 meld/melddoc.py |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)
---
diff --git a/meld/melddoc.py b/meld/melddoc.py
index c319d10..11a0505 100644
--- a/meld/melddoc.py
+++ b/meld/melddoc.py
@@ -192,6 +192,8 @@ class MeldDoc(GObject.GObject):
         uimanager.remove_action_group(self.actiongroup)
         uimanager.remove_ui(self.ui_merge_id)
         self.main_actiongroup = None
+        self.popup_menu = None
+        self.ui_merge_id = None
 
     def on_delete_event(self, appquit=0):
         """Called when the docs container is about to close.