Refactor: move patterns under (legacy) sub-dir

part-of #297

Author: kares

lib/logstash/patterns/core.rb

@@ -1,10 +1,10 @@
 module LogStash
   module Patterns
     module Core
-    extend self
+      extend self
 
       def path
-        ::File.expand_path('../../../patterns', ::File.dirname(__FILE__))
+        ::File.expand_path('../../../patterns/legacy', ::File.dirname(__FILE__))
       end
 
     end