[networking] LBaaS v1 has been removed
[networking] LBaaS v1 has been removed

LBaaS v1 has been removed from neutron-lbaas code base during
Newton cycle. This commit updates the corresponding section.

Change-Id: Ia6b4e1943d0fe6febea8a7d3886e157d42458f0c
Closes-Bug: #1624651

openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals