dash libsai does not support APIs set/get attribute of SAI object/entry

[jimmyzhai]

The implementation of APIs set/get attribute is still missing like below:

static sai_status_t dash_sai_set_{{ api.name }}_attribute(
        {% include 'templates/headers/sai_api_param_object_id.j2' %},
        _In_ const sai_attribute_t *attr)
{
    DASH_LOG_ENTER();
    assert(0 && "sai_set_{{ api.name }}_attribute NYI");
    return SAI_STATUS_FAILURE;
}

static sai_status_t dash_sai_get_{{ api.name }}_attribute(
        {% include 'templates/headers/sai_api_param_object_id.j2' %},
        _In_ uint32_t attr_count,
        _Inout_ sai_attribute_t *attr_list)
{
    DASH_LOG_ENTER();
    assert(0 && "sai_get_{{ api.name }}_attribute NYI");
    return SAI_STATUS_FAILURE;
}