[gtk+] GdkEvent: Unref user_data in free

[Timm Bäder <baedert src gnome org>]

commit 74ce20451ff59d3095df70a98824137a3c31e70d
Author: Timm Bäder <mail baedert org>
Date:   Tue Sep 26 12:49:32 2017 +0200

    GdkEvent: Unref user_data in free
    
    gdk_event_set_user_data refs it and this was creating pretty bad leaks.

 gdk/gdkevents.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/gdk/gdkevents.c b/gdk/gdkevents.c
index 170bcdb..33c2d50 100644
--- a/gdk/gdkevents.c
+++ b/gdk/gdkevents.c
@@ -766,6 +766,7 @@ gdk_event_free (GdkEvent *event)
       private = (GdkEventPrivate *) event;
       g_clear_object (&private->device);
       g_clear_object (&private->source_device);
+      g_clear_object (&private->user_data);
     }
 
   switch (event->any.type)