I checked the various quantum services / resources.
Everything looks ok except for the two DHCP agent which report XXX

jenkins@wip-devstack-1362643791:~/workspace$ quantum net-list
+--------------------------------------+---------+------------------------------------------------------+
| id                                   | name    | subnets                                              |
+--------------------------------------+---------+------------------------------------------------------+
| bd3653b3-e032-4caf-a9b6-3ac1ceb167ef | private | 37bf52d2-2854-49b9-903d-ccbe187d2174 10.1.0.0/24     |
| fe6ba3ff-f527-47b7-b4fa-75212b2f8b6f | nova    | 0adef22a-97a4-4fd0-a6b0-4fa0d59aa3a8 172.24.4.224/28 |
+--------------------------------------+---------+------------------------------------------------------+


jenkins@wip-devstack-1362643791:~/workspace$ quantum subnet-list
+--------------------------------------+------+-----------------+--------------------------------------------------+
| id                                   | name | cidr            | allocation_pools                                 |
+--------------------------------------+------+-----------------+--------------------------------------------------+
| 0adef22a-97a4-4fd0-a6b0-4fa0d59aa3a8 |      | 172.24.4.224/28 | {"start": "172.24.4.226", "end": "172.24.4.238"} |
| 37bf52d2-2854-49b9-903d-ccbe187d2174 |      | 10.1.0.0/24     | {"start": "10.1.0.2", "end": "10.1.0.254"}       |
+--------------------------------------+------+-----------------+--------------------------------------------------+

(quantum) net-external-list
+--------------------------------------+------+------------------------------------------------------+
| id                                   | name | subnets                                              |
+--------------------------------------+------+------------------------------------------------------+
| fe6ba3ff-f527-47b7-b4fa-75212b2f8b6f | nova | 0adef22a-97a4-4fd0-a6b0-4fa0d59aa3a8 172.24.4.224/28 |
+--------------------------------------+------+------------------------------------------------------+

(quantum) router-list
+--------------------------------------+---------+--------------------------------------------------------+
| id                                   | name    | external_gateway_info                                  |
+--------------------------------------+---------+--------------------------------------------------------+
| 81aece45-0919-40a3-9de2-8dccd566b9fb | router1 | {"network_id": "fe6ba3ff-f527-47b7-b4fa-75212b2f8b6f"} |
+--------------------------------------+---------+--------------------------------------------------------+

(quantum) router-port-list router1
+--------------------------------------+------+-------------------+-------------------------------------------------------------------------------------+
| id                                   | name | mac_address       | fixed_ips                                                                           |
+--------------------------------------+------+-------------------+-------------------------------------------------------------------------------------+
| 5aaeb9ce-b52d-4dc5-b371-1964702bd3ff |      | fa:16:3e:4d:d7:95 | {"subnet_id": "0adef22a-97a4-4fd0-a6b0-4fa0d59aa3a8", "ip_address": "172.24.4.226"} |
| d7f515a0-c0f7-40ec-9698-a440ea51d68b |      | fa:16:3e:62:bd:43 | {"subnet_id": "37bf52d2-2854-49b9-903d-ccbe187d2174", "ip_address": "10.1.0.1"}     |
+--------------------------------------+------+-------------------+-------------------------------------------------------------------------------------+

(quantum) l3-agent-list-hosting-router router1
+--------------------------------------+-------------------------+----------------+-------+
| id                                   | host                    | admin_state_up | alive |
+--------------------------------------+-------------------------+----------------+-------+
| 67218f3f-d5ef-4fcc-b21a-ef69afb97822 | wip-devstack-1362643791 | True           | :-)   |
+--------------------------------------+-------------------------+----------------+-------+

(quantum) router-list-on-l3-agent 67218f3f-d5ef-4fcc-b21a-ef69afb97822
+--------------------------------------+---------+--------------------------------------------------------+
| id                                   | name    | external_gateway_info                                  |
+--------------------------------------+---------+--------------------------------------------------------+
| 81aece45-0919-40a3-9de2-8dccd566b9fb | router1 | {"network_id": "fe6ba3ff-f527-47b7-b4fa-75212b2f8b6f"} |
+--------------------------------------+---------+--------------------------------------------------------+

(quantum) dhcp-agent-list-hosting-net nova
+--------------------------------------+-------------------------+----------------+-------+
| id                                   | host                    | admin_state_up | alive |
+--------------------------------------+-------------------------+----------------+-------+
| ab56afc1-d592-4839-85d8-952f33e59073 | wip-devstack-1362643791 | True           | xxx   |
+--------------------------------------+-------------------------+----------------+-------+

(quantum) dhcp-agent-list-hosting-net private
+--------------------------------------+-------------------------+----------------+-------+
| id                                   | host                    | admin_state_up | alive |
+--------------------------------------+-------------------------+----------------+-------+
| ab56afc1-d592-4839-85d8-952f33e59073 | wip-devstack-1362643791 | True           | xxx   |
+--------------------------------------+-------------------------+----------------+-------+

I checked in devstack screen, but I didn't see any special error for the dhcp service. I tried restarting the service, and now I get ":-)". I created new VMs, but still they have the same exact issue.