Align the generated gni files with the new Chromium copyright header

This probably needs some revising (ideally the files would just live in
some BoringSSL branch), but for now just avoid undoing the manual change
done to the pregenerated files in Chromium.

Change-Id: I0435a1478af8265c085d316eb83b394289eb1f67
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/55245
Commit-Queue: Bob Beck <bbe@google.com>
Reviewed-by: Bob Beck <bbe@google.com>
Auto-Submit: David Benjamin <davidben@google.com>

util/generate_build_files.py

diff --git a/util/generate_build_files.py b/util/generate_build_files.py
index 186fb59..1d380b0 100644
--- a/util/generate_build_files.py
+++ b/util/generate_build_files.py
@@ -328,7 +328,7 @@
   def __init__(self):
     self.firstSection = True
     self.header = \
-"""# Copyright (c) 2016 The Chromium Authors. All rights reserved.
+"""# Copyright 2016 The Chromium Authors
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
@@ -387,7 +387,7 @@
 
   def __init__(self):
     self.header = \
-"""# Copyright (c) 2016 The Chromium Authors. All rights reserved.
+"""# Copyright 2016 The Chromium Authors
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.