Generate new LICENSES tree with revised scripts

hack/tools/LICENSES/vendor/github.com/bazelbuild/buildtools/LICENSE

@@ -0,0 +1,17 @@
+= vendor/github.com/bazelbuild/buildtools licensed under: =
+
+Copyright 2016 Google 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.
+
+= vendor/github.com/bazelbuild/buildtools/LICENSE adb52eb384caedba181cd51fbcdf4b99