delete port fail if it is already deleted in nvp

Similar to https://bugs.launchpad.net/neutron/+bug/1291690, but when deleting ports. If the port is already deleted from nvp, the neutron fail to delete it from it's database.

Here is the command output:

sunshine:openpro bhuvan$ neutron net-list
+--------------------------------------+---------------------------------+-------------------------------------------------------+
| id | name | subnets |
+--------------------------------------+---------------------------------+-------------------------------------------------------+
| 048d79c4-17b7-4a5e-b1dc-c7829306431a | openstack-uplink | 9479f0bd-7a2a-4b54-99c3-b858864dca9b |
| 1f740648-85c5-4081-a04d-bba6a3eb6ecf | tempest-net | 66ebd803-21d2-4cdf-a336-61dd421589d4 17.177.36.192/26 |
| 6d382dfd-f826-45d3-8818-48c34f8a8908 | tempest-uplink | 67056b2d-a924-4456-9050-ed0baa0eaf1a 17.176.14.200/29 |
| e5403cc5-a841-4681-b4b5-df03d3fca38e | test-network--tempest-177070938 | 367e7fd0-0cc5-4ec9-9ae0-0d51b31ac184 10.100.0.32/28 |
+--------------------------------------+---------------------------------+-------------------------------------------------------+
sunshine:openpro bhuvan$ neutron net-delete e5403cc5-a841-4681-b4b5-df03d3fca38e
Unable to complete operation on network e5403cc5-a841-4681-b4b5-df03d3fca38e. There are one or more ports still in use on the network.

sunshine:openpro bhuvan$ neutron port-list
+--------------------------------------+------+-------------------+--------------------------------------------------------------------------------------+
| id | name | mac_address | fixed_ips |
+--------------------------------------+------+-------------------+--------------------------------------------------------------------------------------+
| 7d3e834a-b690-4a04-8570-203e9e5605dc | | fa:16:3e:1d:9b:dc | {"subnet_id": "66ebd803-21d2-4cdf-a336-61dd421589d4", "ip_address": "17.177.36.193"} |
| a6a3c2e5-01d3-4215-aef5-103bf46359af | | fa:16:3e:8d:58:1d | {"subnet_id": "367e7fd0-0cc5-4ec9-9ae0-0d51b31ac184", "ip_address": "10.100.0.33"} |
+--------------------------------------+------+-------------------+--------------------------------------------------------------------------------------+
sunshine:openpro bhuvan$ neutron port-delete a6a3c2e5-01d3-4215-aef5-103bf46359af
409-{u'NeutronError': {u'message': u'Port a6a3c2e5-01d3-4215-aef5-103bf46359af has owner network:router_interface and therefore cannot be deleted directly via the port API.', u'type': u'L3PortInUse', u'detail': u''}}
sunshine:openpro bhuvan$ neutron subnet-delete 367e7fd0-0cc5-4ec9-9ae0-0d51b31ac184
409-{u'NeutronError': {u'message': u'Unable to complete operation on subnet 367e7fd0-0cc5-4ec9-9ae0-0d51b31ac184. One or more ports have an IP allocation from this subnet.', u'type': u'SubnetInUse', u'detail': u''}}
sunshine:openpro bhuvan$ neutron router-list
+--------------------------------------+---------------------------+------------------------------------------------------------------------------+
| id | name | external_gateway_info |
+--------------------------------------+---------------------------+------------------------------------------------------------------------------+
| fce78016-32b2-4c69-a0d7-a50c7a171842 | router--tempest-216451384 | null |
| fe674008-cd0f-4e50-b12c-c65daff330aa | tempest-router | {"network_id": "6d382dfd-f826-45d3-8818-48c34f8a8908", "enable_snat": false} |
+--------------------------------------+---------------------------+------------------------------------------------------------------------------+
sunshine:openpro bhuvan$ neutron router-interface-delete fce78016-32b2-4c69-a0d7-a50c7a171842 367e7fd0-0cc5-4ec9-9ae0-0d51b31ac184
404-{u'NeutronError': {u'message': u'Port 8263bc86-4daf-42b5-b49b-83009e558348 could not be found on network afc6b0dc-9f15-41f4-8270-7cb32a3cc12b', u'type': u'PortNotFoundOnNetwork', u'detail': u''}}

Here is the neutron log:

2014-03-17 17:36:21,622 (neutron.plugins.vmware.api_client.eventlet_request): DEBUG eventlet_request _handle_request [0] Completed request 'GET /ws.v1/lswitch/afc6b0dc-9f15-41f4-8270-7cb
32a3cc12b/lport/8263bc86-4daf-42b5-b49b-83009e558348?relations=LogicalPortAttachment': 404
2014-03-17 17:36:21,623 (neutron.plugins.vmware.api_client.client): DEBUG client request Request returns "<httplib.HTTPResponse instance at 0x3a02050>"
2014-03-17 17:36:21,624 (neutron.plugins.vmware.api_client.client): ERROR client request Received error code: 404
2014-03-17 17:36:21,625 (neutron.plugins.vmware.api_client.client): ERROR client request Server Error Message: Entity '8263bc86-4daf-42b5-b49b-83009e558348' not registered.
2014-03-17 17:36:21,625 (neutron.plugins.vmware.nsxlib.switch): ERROR switch get_port Port or Network not found, Error: An unknown exception occurred.
2014-03-17 17:36:21,626 (neutron.api.v2.resource): INFO resource resource remove_router_interface failed (client error): Port 8263bc86-4daf-42b5-b49b-83009e558348 could not be found on n
etwork afc6b0dc-9f15-41f4-8270-7cb32a3cc12b
2014-03-17 17:36:21,628 (neutron.wsgi): INFO log write 17.172.6.117 - - [17/Mar/2014 17:36:21] "PUT /v2.0/routers/fce78016-32b2-4c69-a0d7-a50c7a171842/remove_router_interface.json HTTP/1
.1" 404 319 0.178176