[CE-41] Swarm detection for latest docker version

In the newest versions of docker, swarm is included and the server
version field of docker info does not return any "swarm" addition.
To detect a swarm active machine,I'm proposing to check swarm.cluster.ID
this field is empty for non swarm and contains a string of hexa when
swarm is configured

The change affects src/agent/docker/dockr_swarm.py and consist of
capturing the swarm.cluster.ID and to take that into account as an
alternative swarm detection mechanism
        server_swarm_cluster = client.info()['Swarm']['Cluster']['ID']
        if server_version.startswith('swarm') or server_swarm_cluster != '':

To test, cello was activated with some additional logging.debug
(removed from the release file) in the setup_container_host to show the
creating was happening on swarm machine. Testing was performed on Ubuntu
 server and on Centos (with fix CE-49)

Issue: CE-41
Change-Id: I01c627cdfd142d771a25cd427ef29fe1c9347dc3
Signed-off-by: Daniel Vielvoye <[email protected]>

src/agent/docker/docker_swarm.py

@@ -154,7 +154,8 @@ def detect_daemon_type(daemon_url, timeout=5):
     try:
         client = Client(base_url=daemon_url, version="auto", timeout=timeout)
         server_version = client.info()['ServerVersion']
-        if server_version.startswith('swarm'):
+        server_swarm_cluster = client.info()['Swarm']['Cluster']['ID']
+        if server_version.startswith('swarm') or server_swarm_cluster != '':
             return HOST_TYPES[1]
         else:
             return HOST_TYPES[0]