[gdm] Remove unused variable

[Robert Ancell <rancell src gnome org>]

commit 0da72d7f7aff1bb949289b02002b78a2ceea6309
Author: Robert Ancell <robert ancell canonical com>
Date:   Mon Dec 4 12:18:36 2017 +1300

    Remove unused variable

 daemon/gdm-display.c |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)
---
diff --git a/daemon/gdm-display.c b/daemon/gdm-display.c
index 6a3984a..1b58781 100644
--- a/daemon/gdm-display.c
+++ b/daemon/gdm-display.c
@@ -1460,8 +1460,6 @@ can_create_environment (const char *session_id)
 static gboolean
 already_done_initial_setup_on_this_boot (void)
 {
-        GError *error = NULL;
-
         if (g_file_test (ALREADY_RAN_INITIAL_SETUP_ON_THIS_BOOT, G_FILE_TEST_EXISTS))
                 return TRUE;