Deprecate support for the Nicira NVP plugin

The Nicira NVP plugin was part of Neutron in very early phase but it
was split out to an independent plugin, and was rebranded to NSX-T
plugin. Because current puppet-neutron supports NSX-T plugin, we don't
expect any user is still using that ancient plugin, so let's remove it.

Change-Id: I27a36c3964fd127ae36dc69155cad0332c0a2080

manifests/plugins/nvp.pp

@@ -1,4 +1,4 @@
-#
+# DEPRECAED !!
 # Configure the Nicira NVP plugin for neutron.
 #
 # === Parameters
@@ -43,6 +43,8 @@ class neutron::plugins::nvp (
   include neutron::deps
   include neutron::params
 
+  warning('Support for the Nicira NVP plugin has been deprecated')
+
   Package['neutron'] -> Package['neutron-plugin-nvp']
 
   package { 'neutron-plugin-nvp':

releasenotes/notes/deprecate-nvp-plugin-5c9103fe38c2f6a6.yaml

@@ -0,0 +1,5 @@
+---
+deprecations:
+  - |
+    Support for the Nicira NVP plugin has been deprecated and will be removed
+    in a future release.