Prompted information is not correct when delete a non-existing port

[Yang Yu]

Test Steps:
1. create a network
2. create a port with the network we created in step1
3. delete the port which created in step#2,
4. delete the port again:
http://9.12.17.71:9696/v2.0/ports/62995005-6f39-401e-9e80-0cf07b271bfe
DELETE action, return following error:
{
    "QuantumError": "Port 62995005-6f39-401e-9e80-0cf07b271bfe could not be found on network None"
}
5. I feel confused with "network None".

Expected result:
When delete an non-existing port, I think prompt "QuantumError": "Port 62995005-6f39-401e-9e80-0cf07b271bfe could not be found" is enough, or please pass the correct network name to the error message.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/38104

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/38104
Committed: http://github.com/openstack/neutron/commit/88dc6ea2eb99aa184eec5873218f3ab491abbfd1
Submitter: Jenkins
Branch: master

commit 88dc6ea2eb99aa184eec5873218f3ab491abbfd1
Author: Yang Yu <email address hidden>
Date: Mon Jul 22 14:14:36 2013 +0800

    Prompted error message is not correct for PortNotFound

    When deleting a non-existing port, the error message would be
    "Port XXXX could not be found on network None" for some plugins.
    "network None" is not correct enough here.

    Fixes bug #1203631

    Change-Id: Ie5d1ec99a2726ff3fec07f83f83a12d24613ae57