Fix Skydive analyser 'graph' config section

Like elasticsearch is already deployed by Kolla-ansible it can be used
to store Graph events.

Closes-Bug: #1697638

Change-Id: I1f33e044d33c21516cb3bf8c6fd5bb0745b843c1

ansible/roles/skydive/templates/skydive-analyzer.conf.j2

@@ -57,6 +57,4 @@ storage:
     retry: 60
 
 graph:
-  embeded: true
-  client_timeout: 100
-
+  backend: elasticsearch