Fix a few coding standards issues:

* Remove extra empty lines before private keyword usages.

  specs:

  * Fix one long line;
  * use proc keyword instead of Proc.new.

spec/producer/core/env_spec.rb

@@ -2,7 +2,7 @@ require 'spec_helper'
 
 module Producer::Core
   describe Env do
-    let(:recipe)  { Recipe.new(Proc.new { nil }) }
+    let(:recipe)  { Recipe.new(proc { nil }) }
     subject(:env) { Env.new(recipe) }
 
     describe '#current_recipe' do