Adds acceptance test for Fedora 23

* Adds acceptance test for Fedora 23

* Add vbguest plugin

* Fedora `fedora/23-cloud-base` is missing VirtualBox Guest Plugins:
```
Failed to mount folders in Linux guest. This is usually because
the "vboxsf" file system is not available. Please verify that
the guest additions are properly installed in the guest and
can work properly. The command attempted was:

mount -t vboxsf -o uid=`id -u root`,gid=`getent group vagrant | cut -d: -f3` tmp_vagrant-puppet_environments /tmp/vagrant-puppet/environments
mount -t vboxsf -o uid=`id -u root`,gid=`id -g vagrant` tmp_vagrant-puppet_environments /tmp/vagrant-puppet/environments

The error output from the last command was:

mount: unknown filesystem type 'vboxsf'
```

Gemfile

@@ -13,6 +13,7 @@ group :acceptance do
   gem 'vagrant-digitalocean', '~> 0.5.3'
   gem 'vagrant-aws', '~> 0.4.0'
   gem 'vagrant-rackspace', '~> 0.1.4'
+  gem 'vagrant-vbguest', '~> 0.11.0'
 end
 
 group :docs do

test/acceptance/virtualbox/Vagrantfile

@@ -3,6 +3,7 @@
 
 # plugins don't seem to be auto-loaded from the bundle
 require 'vagrant-puppet-install'
+require 'vagrant-vbguest'
 
 Vagrant.configure('2') do |config|
   config.vm.define :no_config_set do |no_config_set|
@@ -36,6 +37,30 @@ Vagrant.configure('2') do |config|
     trusty_361.vm.provision 'shell', inline: 'puppet --version'
   end
 
+  config.vm.define :fedora_23 do |fedora_23|
+    fedora_23.vm.box = "fedora/23-cloud-base"
+    fedora_23.puppet_install.puppet_version = :latest
+
+    fedora_23.vm.provision :puppet do |puppet|
+      puppet.environment_path = File.expand_path('../../../support/environments', __FILE__)
+      puppet.environment = "vagrant"
+    end
+
+    fedora_23.vm.provision 'shell', inline: 'puppet --version'
+  end
+
+  config.vm.define :fedora_384 do |fedora_384|
+    fedora_384.vm.box = "fedora/23-cloud-base"
+    fedora_384.puppet_install.puppet_version = '3.8.4'
+
+    fedora_384.vm.provision :puppet do |puppet|
+      puppet.environment_path = File.expand_path('../../../support/environments', __FILE__)
+      puppet.environment = "vagrant"
+    end
+
+    fedora_384.vm.provision 'shell', inline: 'puppet --version'
+  end
+
   config.vm.define :trusty_ubuntu_box do |trusty_ubuntu_box|
     trusty_ubuntu_box.puppet_install.puppet_version = :latest
     trusty_ubuntu_box.puppet_install.install_url = 'https://gist.githubusercontent.com/petems/6723c2eedb9d32d7ad97/raw/990ff448f6430aa015e208668a3cecb3f1db0d4b/purge_old_install_new.sh'