[gitg] Avoid use of deprecated pointer API

[Jesse van den Kieboom <jessevdk src gnome org>]

commit 109e47eb8dd310607000d8afdfab584fff4c8f59
Author: Jesse van den Kieboom <jessevdk gnome org>
Date:   Thu Aug 18 13:58:17 2016 +0200

    Avoid use of deprecated pointer API

 libgitg/gitg-diff-view-file-selectable.vala |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)
---
diff --git a/libgitg/gitg-diff-view-file-selectable.vala b/libgitg/gitg-diff-view-file-selectable.vala
index 7ff1858..b415d4b 100644
--- a/libgitg/gitg-diff-view-file-selectable.vala
+++ b/libgitg/gitg-diff-view-file-selectable.vala
@@ -287,7 +287,7 @@ class Gitg.DiffViewFileSelectable : Object
                width = win.get_width();
                height = win.get_height();
 
-               var pointer = Gdk.Display.get_default().get_device_manager().get_client_pointer();
+               var pointer = Gdk.Display.get_default().get_default_seat().get_pointer();
                win.get_device_position(pointer, out x, out y, null);
 
                if (x < 0 || y < 0 || x > width || y > height)