[gitg] Fix deprecation menu.popup()

[Alberto Fanjul <albfan src gnome org>]

commit cf61f15ad81b2fab370323021b5e1968e12e23af
Author: Adwait Rawat <adwait rawat gmail com>
Date:   Fri Mar 22 02:30:42 2019 +0900

    Fix deprecation menu.popup()

 libgitg/gitg-diff-view-file.vala | 11 +----------
 libgitg/gitg-sidebar.vala        | 11 +----------
 2 files changed, 2 insertions(+), 20 deletions(-)
---
diff --git a/libgitg/gitg-diff-view-file.vala b/libgitg/gitg-diff-view-file.vala
index afec0608..d4e31cc9 100644
--- a/libgitg/gitg-diff-view-file.vala
+++ b/libgitg/gitg-diff-view-file.vala
@@ -236,17 +236,8 @@ class Gitg.DiffViewFile : Gtk.Grid
 
                menu.add(copy_file_path);
 
-               uint button = 0;
-               uint evtime = Gdk.CURRENT_TIME;
-
-               if (event != null)
-               {
-                       button = event.button;
-                       evtime = event.time;
-               }
-
                menu.attach_to_widget(d_expander, null);
-               menu.popup(null, null, null, button, evtime);
+               menu.popup_at_pointer(event);
        }
 
        private bool expander_button_press_event(Gtk.Widget widget, Gdk.EventButton? event)
diff --git a/libgitg/gitg-sidebar.vala b/libgitg/gitg-sidebar.vala
index 43fa9c8a..c2541296 100644
--- a/libgitg/gitg-sidebar.vala
+++ b/libgitg/gitg-sidebar.vala
@@ -483,16 +483,7 @@ public class Sidebar : Gtk.TreeView
                menu.show_all();
                menu.attach_to_widget(this, null);
 
-               uint button = 0;
-               uint32 t = Gdk.CURRENT_TIME;
-
-               if (event != null)
-               {
-                       button = event.button;
-                       t = event.time;
-               }
-
-               menu.popup(null, null, null, button, t);
+               menu.popup_at_pointer(event);
                return true;
        }