Wrong exception raised for PortNotFound and NetworkNotFound

[Liyingjun]

Http exception should be HTTPNotFound instead of HTTPBadRequest for PortNotFound/NetworkNotFound in [1]:

[1] http://git.openstack.org/cgit/openstack/nova/tree/nova/api/openstack/compute/contrib/attach_interfaces.py#n124

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/161618

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/161618
Committed: https://git.openstack.org/cgit/openstack/nova/commit/?id=b97abfa9d948389b43479da2c50acb00174958be
Submitter: Jenkins
Branch: master

commit b97abfa9d948389b43479da2c50acb00174958be
Author: liyingjun <email address hidden>
Date: Thu Mar 5 14:31:52 2015 +0800

    Raise HTTPNotFound for Port/NetworkNotFound

    Http exception should be HTTPNotFound instead of HTTPBadRequest for
    PortNotFound/NetworkNotFound for attach interface api.

    Change-Id: Iddbf6f04000f7f4471ac10ae8c7df055af747bd6
    Closes-bug: #1428481