[gnome-mines] Remove obsolete Unity special case

[Robert Roth <robertroth src gnome org>]

commit cd7e87ddf5e8738e092bd7696a6d659822a183b8
Author: Robert Roth <robert roth off gmail com>
Date:   Fri Oct 5 01:00:13 2018 +0300

    Remove obsolete Unity special case

 src/gnome-mines.vala | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)
---
diff --git a/src/gnome-mines.vala b/src/gnome-mines.vala
index e8a2d2e..259dce0 100644
--- a/src/gnome-mines.vala
+++ b/src/gnome-mines.vala
@@ -219,15 +219,11 @@ public class Mines : Gtk.Application
             window.maximize ();
         add_window (window);
 
-        var desktop = Environment.get_variable ("XDG_CURRENT_DESKTOP");
-        if (desktop == null || desktop != "Unity")
-        {
-            var headerbar = new Gtk.HeaderBar ();
-            headerbar.show_close_button = true;
-            headerbar.set_title (_("Mines"));
-            headerbar.show ();
-            window.set_titlebar (headerbar);
-        }
+        var headerbar = new Gtk.HeaderBar ();
+        headerbar.show_close_button = true;
+        headerbar.set_title (_("Mines"));
+        headerbar.show ();
+        window.set_titlebar (headerbar);
 
         bool shell_shows_menubar;
         Gtk.Settings.get_default ().get ("gtk-shell-shows-menubar", out shell_shows_menubar);