gtk: fix possible memory leak about local_err

local_err in gd_vc_gfx_init() is not freed, and we don't use it,
so remove it.

Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

ui/gtk.c

diff --git a/ui/gtk.c b/ui/gtk.c
index 38bf463..9496b8d 100644
--- a/ui/gtk.c
+++ b/ui/gtk.c
@@ -1666,10 +1666,9 @@
                               QemuConsole *con, int idx,
                               GSList *group, GtkWidget *view_menu)
 {
-    Error *local_err = NULL;
     Object *obj;
 
-    obj = object_property_get_link(OBJECT(con), "device", &local_err);
+    obj = object_property_get_link(OBJECT(con), "device", NULL);
     if (obj) {
         vc->label = g_strdup_printf("%s", object_get_typename(obj));
     } else {