List servers in haproxy backend.

    backend
        haproxy backend

    socket
        haproxy stats socket, default ``/var/run/haproxy.sock``

    CLI Example:

    .. code-block:: bash

        salt '*' haproxy.list_servers mysql

def list_servers(backend, socket=DEFAULT_SOCKET_URL, objectify=False):
    '''
    List servers in haproxy backend.

    backend
        haproxy backend

    socket
        haproxy stats socket, default ``/var/run/haproxy.sock``

    CLI Example:

    .. code-block:: bash

        salt '*' haproxy.list_servers mysql
    '''
    ha_conn = _get_conn(socket)
    ha_cmd = haproxy.cmds.listServers(backend=backend)
    return ha_conn.sendCmd(ha_cmd, objectify=objectify)