Delete the vendor/engines/<engine> directory when it's completely emp…

…ty after destroying the extension.

core/lib/generators/refinery/engine/engine_generator.rb

@@ -76,7 +76,7 @@ def generate
         exit(1)
       end
 
-      unless attributes.empty? and self.behavior != :revoke
+      if attributes.any? || self.behavior == :revoke
         Pathname.glob(Pathname.new(self.class.source_root).join('**', '**')).reject{|f| f.directory? or reject_file?(f) }.sort.each do |path|
           unless (engine_path = engine_path_for(path, engine_name)).nil?
             template path, engine_path
@@ -136,6 +136,12 @@ def generate
             puts "rake db:migrate"
             puts "------------------------"
           end
+        else
+          engine_path = destination_pathname.join('vendor', 'engines', engine_plural_name)
+          if Pathname.glob(engine_path.join('**', '*')).all?(&:directory?)
+            say_status :remove, relative_to_original_destination_root(engine_path.to_s), true
+            FileUtils.rm_rf engine_path unless options[:pretend]
+          end
         end
       else
         puts "You must specify at least one field. For help: rails generate refinery:engine"