Update OS kitchen tests dependencies

Related: PROD-26476 (PROD:26476)

Change-Id: Iede4c47fe483a73a2f50f6b82f20b01dc866afff
diff --git a/Gemfile b/Gemfile
index 408029d..c58ebb8 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,6 +4,7 @@
 gem 'test-kitchen'
 if File.exist?('.kitchen.openstack.yml') then
   gem 'kitchen-openstack'
+  gem 'berkshelf'
 else
   gem 'kitchen-docker'
 end