Use psych_yaml_as to avoid collision with Syck.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@33111 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/psych/test_deprecated.rb

@@ -145,7 +145,7 @@ module Psych
     end
 
     class YamlAs
-      yaml_as 'helloworld'
+      psych_yaml_as 'helloworld' # this should be yaml_as but to avoid syck
     end
 
     def test_yaml_as