Do not vendor cookbooks using Berkshelf anymore

Instead, use the Berkshelf support in knife-solo and the
vagrant-berkshelf plugin on Vagrant

cookbooks/seven_zip/attributes/default.rb

@@ -1,31 +0,0 @@
-#
-# Author:: Seth Chisamore (<schisamo@chef.io>)
-# Cookbook Name:: seven_zip
-# Attribute:: default
-#
-# Copyright:: Copyright (c) 2011-2016 Chef Software, Inc.
-#
-# 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.
-#
-
-if node['kernel']['machine'] == 'x86_64'
-  default['seven_zip']['url']          = 'http://www.7-zip.org/a/7z1514-x64.msi'
-  default['seven_zip']['checksum']     = 'cefe1a9092d8a6be68468c33910d6206b40e934fb63cab686c5cccf369fbf712'
-  default['seven_zip']['package_name'] = '7-Zip 15.14 (x64 edition)'
-else
-  default['seven_zip']['url']          = 'http://www.7-zip.org/a/7z1514.msi'
-  default['seven_zip']['checksum']     = 'eaf58e29941d8ca95045946949d75d9b5455fac167df979a7f8e4a6bf2d39680'
-  default['seven_zip']['package_name'] = '7-Zip 15.14'
-end
-
-default['seven_zip']['default_extract_timeout'] = 600