[gtk+] mir: clear screen, keymap and event source when disposing dpy

[Marco Trevisan <marcotrevi src gnome org>]

commit b8925253b66a63594f5d373dc10c564f0d184eb4
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Thu Nov 27 19:25:55 2014 +0100

    mir: clear screen, keymap and event source when disposing dpy

 gdk/mir/gdkmirdisplay.c |    5 +++--
 1 files changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/gdk/mir/gdkmirdisplay.c b/gdk/mir/gdkmirdisplay.c
index dd71ac6..a0a2052 100644
--- a/gdk/mir/gdkmirdisplay.c
+++ b/gdk/mir/gdkmirdisplay.c
@@ -160,8 +160,9 @@ gdk_mir_display_dispose (GObject *object)
 {
   GdkMirDisplay *display = GDK_MIR_DISPLAY (object);
 
-  g_object_unref (display->screen);
-  display->screen = NULL;
+  g_clear_object (&display->screen);
+  g_clear_object (&display->keymap);
+  g_clear_pointer (&display->event_source, g_source_unref);
 
   G_OBJECT_CLASS (gdk_mir_display_parent_class)->dispose (object);
 }