Fix jinja logic operator

Change-Id: Id75215032ae1b199af440b15914347f71002a0f3
diff --git a/docker/swarm.sls b/docker/swarm.sls
index b9183f2..bc2d366 100644
--- a/docker/swarm.sls
+++ b/docker/swarm.sls
@@ -62,7 +62,7 @@
 
 {%- set join_token = swarm.get('join_token', {}).get(swarm.role, join_token[-1]) %}
 
-{%- if join_token && join_token != "unknown" %}
+{%- if join_token and join_token != "unknown" %}
 
 docker_swarm_join:
   cmd.run: