[gnome-panel] menu: stop using deprecated sd_seat_can_multi_session

[Alberts Muktupāvels <muktupavels src gnome org>]

commit ebc35dce6eeeee0157e044d30e8ba176a8293d3e
Author: Alberts Muktupāvels <alberts muktupavels gmail com>
Date:   Fri Sep 4 19:05:50 2020 +0300

    menu: stop using deprecated sd_seat_can_multi_session
    
    All seats supports multiple sessions:
    https://github.com/systemd/systemd/pull/15337
    https://github.com/systemd/systemd/pull/15459
    
    sd_seat_can_multi_session function has been deprecated and always
    returns true with systemd 246 or newer.

 modules/menu/gp-lock-logout.c | 10 ----------
 1 file changed, 10 deletions(-)
---
diff --git a/modules/menu/gp-lock-logout.c b/modules/menu/gp-lock-logout.c
index 4b8bb9d3a..19be2dc17 100644
--- a/modules/menu/gp-lock-logout.c
+++ b/modules/menu/gp-lock-logout.c
@@ -27,7 +27,6 @@
 #include <gdm/gdm-user-switching.h>
 #include <glib/gi18n-lib.h>
 #include <libgnome-panel/gp-image-menu-item.h>
-#include <systemd/sd-login.h>
 
 struct _GpLockLogout
 {
@@ -507,15 +506,6 @@ shutdown_activate_cb (GtkWidget    *item,
 static gboolean
 get_can_switch_user (GpLockLogout *lock_logout)
 {
-  const gchar *xdg_seat;
-
-  xdg_seat = g_getenv ("XDG_SEAT");
-  if (xdg_seat != NULL && *xdg_seat != '\0')
-    {
-      if (sd_seat_can_multi_session (xdg_seat) == 0)
-        return FALSE;
-    }
-
   return TRUE;
 }