Replace Apache 2.0 boilerplate/reference with SPDX

Change-Id: I691c4893e500aa791868adb82573ef2357805faf

extract_utils.sh

@@ -1,19 +1,9 @@
 #!/bin/bash
 #
 # Copyright (C) 2016 The CyanogenMod Project
-#               2017-2020 The LineageOS Project
+# Copyright (C) 2017-2020 The LineageOS Project
 #
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-# http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
+# SPDX-License-Identifier: Apache-2.0
 #
 
 PRODUCT_COPY_FILES_LIST=()