Fix default openstack_version in reclass

Set it to latest supported version in release - queens

Change-Id: I1332ebabca8b2973bac31b2cdcb9f07304be8ddb
(cherry picked from commit 2676316323c45cdddcb8ab4689901ad409e9e4f4)
diff --git a/defaults/openstack/init.yml b/defaults/openstack/init.yml
index d73dc71..ecac1b6 100644
--- a/defaults/openstack/init.yml
+++ b/defaults/openstack/init.yml
@@ -19,7 +19,7 @@
     openstack_memcache_security_strategy: 'ENCRYPT'
     openstack_memcached_proto_tcp_enabled: True
     openstack_memcached_proto_udp_enabled: False
-    openstack_version: ocata
+    openstack_version: queens
     openstack_old_version: ${_param:openstack_version}
     openstack_upgrade_enabled: False
     # Cinder