Updated openstack/openstack
Project: openstack/neutron  575b3fe84ca1bb6ef87db379cae34040abfca89e

Remove ryu plugin

Ryu plugin was marked deprecated in Juno.
This commit actually removes the code for Kilo.

We (Ryu team) recommend users to migrate to ofagent, on which
we aim to concentrate our development resources by this deprecation.

DocImpact
Partial-Bug: #1391714
Change-Id: I4916ce3c246730dc00516404471f8a1a008e27b6