Add the Apache license to the overcloud-delete playbook

This is present in the other playbooks but wasn't added to overcloud
delete.

Change-Id: I856ca2cac31b100995c6a3e6b53199b921b2b627

tripleo_ansible/playbooks/overcloud-delete.yaml

@@ -1,4 +1,18 @@
 ---
+# Copyright 2019 Red Hat, Inc.
+# All Rights Reserved.
+#
+# 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.
 
 - connection: local
   hosts: localhost