Add test for upgrading from previous version of oss to current

test/integration/helpers/serverspec/oss_upgrade_spec.rb

@@ -0,0 +1,9 @@
+require 'spec_helper'
+
+shared_examples 'oss_upgrade::init' do |vars|
+  describe 'version check' do
+    it 'should be reported as version '+vars['es_version'] do
+      expect(curl_json('http://localhost:9200')['version']['number']).to eq(vars['es_version'])
+    end
+  end
+end