prevented _posts from being copied to the destination directory

lib/jekyll/site.rb

@@ -112,8 +112,8 @@ module Jekyll
 
       # we need to make sure to process _posts *first* otherwise they 
       # might not be available yet to other templates as {{ site.posts }}
-      if entries.include?('_posts')
-        entries.delete('_posts')
+      if directories.include?('_posts')
+        directories.delete('_posts')
         read_posts(dir)
       end
       [directories, files].each do |entries|

test/test_generated_site.rb

@@ -29,4 +29,8 @@ class TestGeneratedSite < Test::Unit::TestCase
     assert_equal 1, published.size
     assert_equal "published.html", published.first
   end
+
+  def test_posts_directory_not_copied
+    assert !File.exist?(File.join(dest_dir, '_posts'))
+  end
 end