Some OVS bridges may lack OpenFlow10 protocol

[Oleg Bondarev]

After commit https://review.opendev.org/c/openstack/neutron/+/371455 OVSAgentBridge.setup_controllers() no longer sets OpenFlow10 protocol for the bridge, instead it was moved to ovs_lib.OVSBridge.create().
However some (custom) OVS bridges could be created by nova/os-vif when plugging VM interface.
For such bridges neutron does not call create(), only setup_controllers() - as a result such bridges support only OpenFlow13 and ovs-ofctl command fails:

2020-11-24T20:18:38Z|00001|vconn|WARN|unix:/var/run/openvswitch/br01711489f-fe.24081.mgmt: version negotiation failed (we support version 0x01, peer supports version 0x04)
ovs-ofctl: br01711489f-fe: failed to connect to socket (Broken pipe)

Fix: return setting of OpenFlow10 (along with OpenFlow13) to setup_controllers(). It's doesn't hurt even if bridge already has OpenFlow10 in supported protocols.

[Rodolfo Alonso (rodolfo-alonso-hernandez)]

Patch: https://review.opendev.org/c/openstack/neutron/+/764150

[Oleg Bondarev (obondarev)]

Fix: https://review.opendev.org/c/openstack/neutron/+/764150

[OpenStack Infra (hudson-openstack)]

This issue was fixed in the openstack/neutron 18.0.0.0rc1 release candidate.