Copy YAML::Store to Syck::Store to keep it from yamler.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@32075 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/syck/test_yamlstore.rb

@@ -1,6 +1,6 @@
 require 'test/unit'
-require 'syck'
 require 'yaml/store'
+Syck::Store = YAML::Store unless defined?(Syck::Store)
 
 module Syck
   class YAMLStoreTest < Test::Unit::TestCase