Neutron ovs plugin should not require vswitch::ovs

I don't see any reason openvswitch components should be required on the same
machine than the neutron ovs *plugin*. It is definitely required for the
neutron ovs *agent* though.

Conflicts:
	manifests/plugins/ovs.pp

Change-Id: I1d7128f8a79d788b48af4acf504d48a19e8fe12b
Preparing quantum for 2.2.0 release

Updated version in Modulefile.
Added release notes to README.md.

Could not cherry-pick back from 2b5069f5 because of quantum/neutron
name change.

Change-Id: Ia21b8f8c70d85b083f57b639e0ff927ad381454c