config file fixes

`zoo.cfg` template has an error with `cluster_servers` configuration.

Current configuration:

    # ....
    server.0=:2888:3888
    server.1=:2888:3888
    server.2=:2888:3888

Expected configuration (https://zookeeper.apache.org/doc/r3.1.2/zookeeperStarted.html, section 'Running Replicated ZooKeeper'):

    # ...
    server.1=zoo1:2888:3888
    server.2=zoo2:2888:3888
    server.3=zoo3:2888:3888

role override_attributes:

    "zookeper": {
               "cluster_servers": [
                {
                    "name": "zoo1",
                    "zookeeper":
                    {
                        "ipaddress": "zoo1",
                        "fqdn": "zoo1.example.com",
                        "peer_port": 2888,
                        "leader_port": 3888
                    }
                },
                {
                    "name": "zoo2",
                    "zookeeper":
                    {
                        "ipaddress": "zoo2",
                        "fqdn": "zoo2.example.com",
                        "peer_port": 2888,
                        "leader_port": 3888
                    }
                },
                {
                    "name": "zoo3",
                    "zookeeper":
                    {
                        "ipaddress": "zoo3",
                        "fqdn": "zoo3.example.com",
                        "peer_port": 2888,
                        "leader_port": 3888
                    }
                }
    }