[CI] Add JUnit to X-Pack

Author: picandocodigo

elasticsearch-xpack/Gemfile

@@ -9,6 +9,7 @@ gemspec
 
 group :development do
   gem 'rspec'
+  gem 'rspec_junit_formatter'
   if defined?(JRUBY_VERSION)
     gem 'pry-nav'
   else

elasticsearch-xpack/spec/spec_helper.rb

@@ -34,4 +34,5 @@ def self.included(context)
   config.include(HelperModule)
   config.formatter = 'documentation'
   config.color = true
+  config.add_formatter('RspecJunitFormatter', '../elasticsearch-api/tmp/elasticsearch-xpack-junit.xml')
 end