See if jail service is actually enabled on boot

    CLI Example:

    .. code-block:: bash

        salt '*' jail.is_enabled <jail name>

def is_enabled():
    '''
    See if jail service is actually enabled on boot

    CLI Example:

    .. code-block:: bash

        salt '*' jail.is_enabled <jail name>
    '''
    cmd = 'service -e'
    services = __salt__['cmd.run'](cmd, python_shell=False)
    for service in services.split('\\n'):
        if re.search('jail', service):
            return True
    return False