Adding Vagrant 1.7.1 due to bug w/ vmware in 1.7.2

Casks/vagrant171.rb

@@ -0,0 +1,13 @@
+cask :v1 => 'vagrant171' do
+  version '1.7.1'
+  sha256 'eaeb3ad6624ccaeaefa6fc7a77a2f5d9640ef9385c5eeebdb90602d5f2011176'
+
+  url "https://dl.bintray.com/mitchellh/vagrant/vagrant_#{version}.dmg"
+  homepage 'http://www.vagrantup.com'
+  license :mit
+
+  pkg 'Vagrant.pkg'
+
+  uninstall :script => { :executable => 'uninstall.tool', :input => %w[Yes] },
+            :pkgutil => 'com.vagrant.vagrant'
+end