[build] Remove early JRuby/rubygems backward compat code

Author: chadlwilson

Rakefile

@@ -52,16 +52,7 @@ desc "Unpack the rack gem"
 task :unpack_gem => "target" do |t|
   target = File.expand_path(t.prerequisites.first)
   spec = Gem.loaded_specs['rack']
-  # JRuby <= 1.7.20 does not handle respond_to? with method_missing right
-  # ... issue with Bundler::StubSpecification wrapping (in bundler 1.10.x)
-  unless ( gem_file = spec.cache_file rescue nil )
-    #if defined?(::Bundler) && ::Bundler.const_defined?(:StubSpecification) # since Bundler 1.10.1
-    #  spec = spec.to_spec if spec.is_a?(::Bundler::StubSpecification)
-    #else
-    #  spec = spec.to_spec if spec.respond_to?(:to_spec)
-    #end
-    gem_file = File.join(spec.base_dir, 'cache', spec.file_name)
-  end
+  gem_file = spec.respond_to?(:cache_file) ? spec.cache_file : File.join(spec.base_dir, 'cache', spec.file_name)
   unless uptodate?("#{target}/vendor/rack.rb", [__FILE__, gem_file])
     mkdir_p "target/vendor"
     require 'rubygems/installer'
@@ -187,9 +178,9 @@ task :gem => [target_jar, target_jruby_rack, target_jruby_rack_version] do
       gem.homepage = %q{http://jruby.org}
       gem.required_ruby_version = '>= 3.1.0' # JRuby >= 9.4
     end
-    defined?(Gem::Builder) ? Gem::Builder.new(gemspec).build : begin
-      require 'rubygems/package'; Gem::Package.build(gemspec)
-    end
+
+    require 'rubygems/package'
+    Gem::Package.build(gemspec)
     File.open('jruby-rack.gemspec', 'w') { |f| f << gemspec.to_ruby }
     mv FileList['*.gem'], '..'
   end