[2.20-Build 64] vRouter on TSN does not propagate DHCP request

[Daisuke Nakajima]

vRouter on TSN does not propagate DHCP request even though DHCP is disable in attribute of virtual-network.
ARP packets are propagated to other VTEP, but DHCP are not.

Please see attached pcap.

[Daisuke Nakajima (dnakajima)]

Virtual-network JSON
{
    "virtual-network": {
        "display_name": "NoDHCP",
        "flood_unknown_unicast": false,
        "fq_name": [
            "default-domain",
            "demo",
            "NoDHCP"
        ],
        "href": "http://172.27.113.209:8082/virtual-network/a60b8b08-640e-497d-a21f-3f819d9b7a01",
        "id_perms": {
            "created": "2015-07-23T09:55:06.543704",
            "creator": null,
            "description": null,
            "enable": true,
            "last_modified": "2015-07-23T09:55:06.805423",
            "permissions": {
                "group": "admin",
                "group_access": 7,
                "other_access": 7,
                "owner": "admin",
                "owner_access": 7
            },
            "user_visible": true,
            "uuid": {
                "uuid_lslong": 11682125784349899265,
                "uuid_mslong": 11964809703194511741
            }
        },
        "instance_ip_back_refs": [
            {
                "attr": null,
                "href": "http://172.27.113.209:8082/instance-ip/1907ef8e-32a2-495a-bdab-19960cb89fc6",
                "to": [
                    "1907ef8e-32a2-495a-bdab-19960cb89fc6"
                ],
                "uuid": "1907ef8e-32a2-495a-bdab-19960cb89fc6"
            },
            {
                "attr": null,
                "href": "http://172.27.113.209:8082/instance-ip/1952c1de-ae33-489b-b44f-8b8739e8c500",
                "to": [
                    "1952c1de-ae33-489b-b44f-8b8739e8c500"
                ],
                "uuid": "1952c1de-ae33-489b-b44f-8b8739e8c500"
            }
        ],
        "is_shared": false,
        "name": "NoDHCP",
        "network_ipam_refs": [
            {
                "attr": {
                    "ipam_subnets": [
                        {
                            "addr_from_start": true,
                            "allocation_pools": [],
                            "default_gateway": "20.0.0.1",
                            "dhcp_option_list": {
                                "dhcp_option": [
                                    {
                                        "dhcp_option_name": "6",
                                        "dhcp_option_value": "0.0.0.0"
                                    }
                                ]
                            },
                            "dns_server_address": "20.0.0.2",
                            "enable_dhcp": false,
                            "host_routes": {
                                "route": []
                            },
                            "subnet": {
                                "ip_prefix": "20.0.0.0",
                                "ip_prefix_len": 24
                            },
                            "subnet_uuid": "0b5a3608-57b4-454a-9475-552bf27b7d7b"
                        }
                    ]
                },
                "href": "http://172.27.113.209:8082/network-ipam/644962c8-b54f-497b-b3b1-7cb901fe59b6",
                "to": [
                    "default-domain",
                    "default-project",
             ...