nicira plugin - metadata access ops lead to eventlet deadlock

[Salvatore Orlando]

This is the usual problem of the eventlet deadlock between rpc and mysql database, first reported in bug 1086173
In this case it is exacerbated by the fact nvp uses eventlet too.

This patch ensures NVP plugin operations are not encapsulated in a mysql transaction, thus removing the long transaction which might end up deadlocking with state reporting operations from the dhcp agent.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/38380

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/38380
Committed: http://github.com/openstack/neutron/commit/2d335360866b68586ed00a7b7a725ccdbb0f9c62
Submitter: Jenkins
Branch: master

commit 2d335360866b68586ed00a7b7a725ccdbb0f9c62
Author: Salvatore Orlando <email address hidden>
Date: Tue Jul 23 23:50:07 2013 +0200

    Remove long db transaction for metadata access network

    Bug 1204277

    Removes nested transactions wrapping plugin ops, and adds
    rollback code where required.
    Also ensures NeutronPlugin.py does not attempt to remove router
    ports twice.

    Change-Id: I299d4ed688a70b6dff506c999355661cf783ae26