Deprecate oslo_config resource

... because /etc/oslo/oslo.conf has never been actually used.

Change-Id: Ib327d97b13877b5ce2651e5a4f15b9d11c939000

lib/puppet/provider/oslo_config/ini_setting.rb

@@ -3,6 +3,11 @@ Puppet::Type.type(:oslo_config).provide(
   :parent => Puppet::Type.type(:openstack_config).provider(:ini_setting)
 ) do
 
+  def create
+    super
+    warning('oslo_config is deprecated, and will be removed in a future release')
+  end
+
   def self.file_path
     '/etc/oslo/oslo.conf'
   end

releasenotes/notes/deprecate-oslo_config-fcd5be0a4c358ba3.yaml

@@ -0,0 +1,5 @@
+---
+deprecations:
+  - |
+    The ``oslo_config`` resource has been deprecated and will be removed in a
+    future release.