Do not vendor cookbooks using Berkshelf anymore

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

cookbooks/composer/recipes/install.rb

@@ -1,36 +0,0 @@
-#
-# Cookbook Name:: composer
-# Recipe:: install
-#
-# Copyright (c) 2016, David Joos
-#
-
-include_recipe node['composer']['php_recipe']
-
-if node['platform'] == 'windows'
-  windows_package 'Composer - PHP Dependency Manager' do
-    source node['composer']['url']
-    options %w(
-      /VERYSILENT
-    ).join(' ')
-  end
-
-  install_dir = "#{node['composer']['install_dir'].tr('/', '\\')}\\bin"
-
-  ENV['PATH'] += ";#{install_dir}"
-  windows_path install_dir
-else
-  log '[composer] phar (PHP archive) not supported' do
-    level :warn
-    not_if "php -m | grep 'Phar'"
-  end
-
-  file = node['composer']['install_globally'] ? "#{node['composer']['install_dir']}/composer" : "#{node['composer']['install_dir']}/composer.phar"
-
-  remote_file file do
-    source node['composer']['url']
-    mode node['composer']['mask']
-    action :create
-    not_if { ::File.exist?(file) }
-  end
-end