Fix Vagrant to add workaround for Windows mounting '/var/cache/apt'

Vagrantfile

@@ -36,9 +36,12 @@ Vagrant::Config.run do |config|
   # Share a folder with the guest VM for storing downloaded packages. This
   # makes rebuilding VMs faster by only downloading packages if needed.
   require "fileutils"
-  apt_cache = "tmp/vagrant_apt_cache"
-  FileUtils.mkdir_p("#{apt_cache}/archives/partial")
-  config.vm.share_folder "vagrant-apt-cache", "/var/cache/apt", apt_cache, :nfs => defined?(NFS) ? NFS : false
+  require "rbconfig"
+  unless RbConfig::CONFIG['host_os'] =~ /mswin|mingw/
+    apt_cache = "tmp/vagrant_apt_cache"
+    FileUtils.mkdir_p("#{apt_cache}/archives/partial")
+    config.vm.share_folder "vagrant-apt-cache", "/var/cache/apt", apt_cache, :nfs => defined?(NFS) ? NFS : false
+  end
 
   # Use more memory so badly-designed programs like Bundler can work.
   config.vm.customize do |vm|