tests/repo: Drop modeline from top of file

As per commit 6e4146a3.

Signed-off-by: Philip Withnall <withnall@endlessm.com>

Closes: #1203
Approved by: cgwalters

tests/test-repo.c

@@ -1,5 +1,4 @@
-/* -*- mode: C; c-file-style: "gnu"; indent-tabs-mode: nil; -*-
- *
+/*
  * Copyright © 2017 Endless Mobile, Inc.
  *
  * This library is free software; you can redistribute it and/or