L->M: neutron-openvswitch charm not rendering openvswitch_agent.ini

[JuanJo Ciarlante]

Context is similar to lp#1571634, but workaround mentioned
there on comment#1 doesn't trigger openvswitch_agent.ini
rendering.

Issue shows itself as ERRORed nova VMs from PortBindingFailed
(see below paste for nova-compute.log details)

Environment and versions:
* openstack HA deploy w/1604 charms release
* bzr charms branches from trunk:
- nova-compute r226
- neutron-api r205
- neutron-openvswitch r123

* compute node state: http://paste.ubuntu.com/20510014/:
- nova-compute.log, openvswitch-agent.log
- package versions
- neutron.conf, openvswitch_agent.ini

FYI this is an openstack install that has gone thru
I->J->K->L->M upgrade path, by means of openstack-origin,
hitting several bugs on the path[0][1][2][3], applying
workarounds as noted on respective bugs, to be able to reach Mitaka.

[0] https://bugs.launchpad.net/charms/+source/cinder/+bug/1595915
[1] https://bugs.launchpad.net/keystone/+bug/1572341
[2] https://bugs.launchpad.net/charms/+source/neutron-api/+bug/1596594
[3] https://bugs.launchpad.net/charms/+source/nova-cloud-controller/+bug/1595966