Add a possibility to deploy Elasticsearch 5.x version

Elasticsearch 2.x version is deployed by default

Change-Id: I78e714807cf5925a9619961ab145f27ef0210652
diff --git a/tests/pillar/single.sls b/tests/pillar/single.sls
index c4f54e0..eec8541 100644
--- a/tests/pillar/single.sls
+++ b/tests/pillar/single.sls
@@ -9,3 +9,4 @@
     index:
       shards: 1
       replicas: 0
+    version: 2