[neutron] Switching Ocata branch to Extended maintenance

Hello and happy new year, as discussed in our final 2018 meeting [0], we plan to switch the Ocata branch of Neutron to Extended maintenance [1]. There will be a final Ocata release for Neutron itself. Stadium projects backports only included test fixes so do not really need a final release. We will then mark the branch as ocata-em. Any comments or objections? Especially from driver projects maintainers, as these have independent releases. [0] http://eavesdrop.openstack.org/meetings/networking/2018/networking.2018-12-1... [1] https://docs.openstack.org/project-team-guide/stable-branches.html#extended-... -- Bernard Cafarelli