Add monkeypatch for Hash to work around vagrant-aws

See mitchellh/vagrant-aws#566

Since we test the bosh-agent against linux and windows, we started
testing against go1.14 on windows and go1.13 on linux. I decided to
update the bosh-agent linux docker image to install go1.14.

The new docker image brought Ruby 2.5+ was installed and vagrant-aws needed to be updated.
I decided to keep going and update the plugin
(d6d7ba9).

This led to this error with vagrant-aws and Ruby's i18n. I could undo
all of this by pinning Ruby in our docker image so that none of these
dependencies are updated, but I think the risk of keeping this
monkeypatch around for a bit is fine.

integration/windows/Vagrantfile

@@ -167,6 +167,18 @@ Pop-Location
 Pop-Location
 SHELL
 
+# https://github.com/mitchellh/vagrant-aws/issues/566
+class Hash
+  def slice(*keep_keys)
+    h = {}
+    keep_keys.each { |key| h[key] = fetch(key) if has_key?(key) }
+    h
+  end unless Hash.method_defined?(:slice)
+  def except(*less_keys)
+    slice(*keys - less_keys)
+  end unless Hash.method_defined?(:except)
+end
+
 Vagrant.configure(2) do |config|
   config.vm.provider :aws do |aws, override|
     aws.instance_type = "m4.large"