[gtk] MenuButton: Disconnect newly added signal handler

[Daniel Boles <dboles src gnome org>]

commit 279344a2e692e71961c3269caa7f72ce3aa0222a
Author: Daniel Boles <dboles src gmail com>
Date:   Sun Apr 22 16:25:07 2018 +0100

    MenuButton: Disconnect newly added signal handler
    
    Otherwise, we do stuff we shouldn't, as the failing pipeline showed:
    https://gitlab.gnome.org/GNOME/gtk/pipelines/9431
    
    https://gitlab.gnome.org/GNOME/gtk/issues/199

 gtk/gtkmenubutton.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)
---
diff --git a/gtk/gtkmenubutton.c b/gtk/gtkmenubutton.c
index 474f38b831..6df1985218 100644
--- a/gtk/gtkmenubutton.c
+++ b/gtk/gtkmenubutton.c
@@ -953,6 +953,12 @@ update_popover_direction (GtkMenuButton *menu_button)
     }
 }
 
+static void
+popover_destroy_cb (GtkMenuButton *menu_button)
+{
+  gtk_menu_button_set_popover (menu_button, NULL);
+}
+
 /**
  * gtk_menu_button_set_direction:
  * @menu_button: a #GtkMenuButton
@@ -1026,6 +1032,9 @@ gtk_menu_button_dispose (GObject *object)
 
   if (priv->popover)
     {
+      g_signal_handlers_disconnect_by_func (priv->popover,
+                                            popover_destroy_cb,
+                                            object);
       gtk_popover_set_relative_to (GTK_POPOVER (priv->popover), NULL);
       priv->popover = NULL;
     }
@@ -1090,12 +1099,6 @@ gtk_menu_button_get_use_popover (GtkMenuButton *menu_button)
   return priv->use_popover;
 }
 
-static void
-popover_destroy_cb (GtkMenuButton *menu_button)
-{
-  gtk_menu_button_set_popover (menu_button, NULL);
-}
-
 /**
  * gtk_menu_button_set_popover:
  * @menu_button: a #GtkMenuButton
@@ -1128,6 +1131,9 @@ gtk_menu_button_set_popover (GtkMenuButton *menu_button,
       g_signal_handlers_disconnect_by_func (priv->popover,
                                             menu_deactivate_cb,
                                             menu_button);
+      g_signal_handlers_disconnect_by_func (priv->popover,
+                                            popover_destroy_cb,
+                                            menu_button);
 
       gtk_popover_set_relative_to (GTK_POPOVER (priv->popover), NULL);
     }