* lib/rubygems/specification.rb (Gem::Specification#to_yaml):
  use Gem::NoAliasYAMLTree.create instead of Gem::NoAliasYAMLTree.new
  to suppress deprecated warnings.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@41148 b2dd03c8-39d4-4d8f-98ff-823fe69b080e