Upstream has just removed lbaasv1 from openstack-lbaas
(https://review.openstack.org/286381).
Let's follow them and provide a working lbaas deployment for our users
on Newton.
- Switch-on lbaasv2 by default instead of lbaasv1 to follow what upstream Neutron is doing
in https://review.openstack.org/286381 and also switch default device_driver to be
neutron_lbaas.drivers.haproxy.namespace_driver.HaproxyNSDriver
- remove lbaasv1 support.
- enable_v1 and enable_v2 are deprecated in neutron::agents::lbaas.
Change-Id: I1c032c53b61face152bb37dfac4646db11403e4e