Delete unused discovery_url for swarm

The swarmnode of Swarm bay don't need discovery_url, so let's
delete it from heat templates.

Change-Id: I48f775e795e1985ada9da7d7660f159df13da7ac

magnum/drivers/swarm_fedora_atomic_v1/templates/cluster.yaml

@@ -382,7 +382,6 @@ resources:
           fixed_network_id: {get_resource: fixed_network}
           fixed_subnet_id: {get_resource: fixed_subnet}
           external_network: {get_param: external_network}
-          discovery_url: {get_param: discovery_url}
           http_proxy: {get_param: http_proxy}
           https_proxy: {get_param: https_proxy}
           no_proxy: {get_param: no_proxy}

magnum/drivers/swarm_fedora_atomic_v1/templates/swarmmaster.yaml

@@ -280,7 +280,6 @@ resources:
           params:
             "$ETCD_SERVER_IP": {get_param: etcd_server_ip}
             "$NODE_IP": {get_attr: [swarm_master_eth0, fixed_ips, 0, ip_address]}
-            "$DISCOVERY_URL": {get_param: discovery_url}
             "$WAIT_HANDLE_ENDPOINT": {get_attr: [master_wait_handle, endpoint]}
             "$WAIT_HANDLE_TOKEN": {get_attr: [master_wait_handle, token]}
             "$HTTP_PROXY": {get_param: http_proxy}

magnum/drivers/swarm_fedora_atomic_v1/templates/swarmnode.yaml

@@ -51,10 +51,6 @@ parameters:
     type: string
     description: network range for flannel overlay network
 
-  discovery_url:
-    type: string
-    description: url provided for node discovery
-
   http_proxy:
     type: string
     description: http proxy address for docker