Kudu deploy.py script should identify clusters by their "displayName"

Clusters in Cloudera Manager appear to have two names 1) "name" and 2) "displayName". The "name" seems to be an internal identifier, whereas "displayName" is shown in the web UI. The deployment script searches for clusters by the "name"

def find_cluster(api, cluster_name):
    all_clusters = api.get_all_clusters()
    if not cluster_name and len(all_clusters) > 1:
        raise Exception("Cannot use implicit cluster; there is more than one available")

    for cluster in all_clusters:
        if (cluster_name and cluster.name == cluster_name) or not cluster_name:
            print "Found cluster: %s" % (cluster.name,)
            return cluster

    if cluster_name:
        message = "Cannot find cluster: %s" % (cluster_name,)

which can lead to confusion when users aren't aware of the difference in names. The deploy.py script should probably just search for clusters by "displayName". However if users are aware of both names they could still be confused as to which is is use. Maybe that can be sovled by clarifying the CLI arg description.