taas can create tap-flow on the source port down without any error info but new rules not added even the port is up later

Openstack version: Queens

Let's Reproduce the bug:

1.create a tap-flow on a neutron port down, we can get the success result on the console
# neutron tap-flow-create --name src1 --tenant-id 94b35ccc09164772a833e433b81c3e25 --port 62cfae8e-7770-4527-91ca-b1ba7b9af0bd --tap-service c1cf4617-cb26-44d0-9a74-d0c2f55aef41 --direction BOTH
neutron CLI is deprecated and will be removed in the future. Use openstack CLI instead.
Created a new tap_flow:
+----------------+--------------------------------------+
| Field | Value |
+----------------+--------------------------------------+
| description | |
| direction | BOTH |
| id | 2e861b97-bc6f-401c-a488-bc7f821fc3dc |
| name | src1 |
| project_id | 94b35ccc09164772a833e433b81c3e25 |
| source_port | 62cfae8e-7770-4527-91ca-b1ba7b9af0bd |
| status | ACTIVE |
| tap_service_id | c1cf4617-cb26-44d0-9a74-d0c2f55aef41 |
| tenant_id | 94b35ccc09164772a833e433b81c3e25 |
+----------------+--------------------------------------+

note the flow source port is down now

# openstack port list | grep 62cfae8e-7770-4527-91ca-b1ba7b9af0bd
| 62cfae8e-7770-4527-91ca-b1ba7b9af0bd | | fa:16:3e:de:9d:a7 | ip_address='192.168.101.9', subnet_id='2b22fb1e-32fc-4782-ac64-f3d93f46f4cf' | DOWN |

2.start the Vm binding the port, now the port is up

| 62cfae8e-7770-4527-91ca-b1ba7b9af0bd | | fa:16:3e:de:9d:a7 | ip_address='192.168.101.9', subnet_id='2b22fb1e-32fc-4782-ac64-f3d93f46f4cf' | ACTIVE |

3.After a while, Let's check the br-int openflow rules on which there is the source port,I do not see the rules which shoud be added by tap-flow-create on br-int,you can verify it by execute:
# ovs-ofctl dump-flows br-int | grep mod_vlan_vid

and the result is empty.