$NetBSD$

Stop calling obsolete method.

--- Rakefile.orig	2009-06-12 16:42:31.000000000 +0900
+++ Rakefile
@@ -1,5 +1,4 @@
 require 'rubygems'
-Gem::manage_gems
 require 'rake/gempackagetask'
 
 require 'maruku_gem'
