Add the #action API to the provider plugin

lib/vagrant/plugin/v1/provider.rb

@@ -5,6 +5,14 @@ module Vagrant
       # is responsible for creating compute resources to match the needs
       # of a Vagrant-configured system.
       class Provider
+        # This should return an action callable for the given name.
+        #
+        # @param [Symbol] name Name of the action.
+        # @return [Object] A callable action sequence object, whether it
+        #   is a proc, object, etc.
+        def action(name)
+          nil
+        end
       end
     end
   end

test/unit/vagrant/plugin/v1/provider_test.rb

@@ -0,0 +1,9 @@
+require File.expand_path("../../../../base", __FILE__)
+
+describe Vagrant::Plugin::V1::Provider do
+  let(:instance) { described_class.new }
+
+  it "should return nil by default for actions" do
+    instance.action(:whatever).should be_nil
+  end
+end