Update Travis settings for Rubinius

/cc @brixen

.travis.yml

@@ -1,8 +1,3 @@
-before_install:
-  - gem update bundler
-  - bundle --version
-  - gem update --system 2.1.11
-  - gem --version
 bundler_args: --without development
 gemfile:
   - Gemfile
@@ -14,7 +9,7 @@ rvm:
   - 1.9.3
   - 2.0.0
   - 2.1.0
-  - rbx
+  - rbx-2
   - ruby-head
 matrix:
   include:

Gemfile

@@ -20,7 +20,7 @@ end
 
 group :test do
   gem 'coveralls', :require => false
-  gem 'json', '>= 1.8.1', :platforms => [:jruby, :rbx, :ruby_18, :ruby_19]
+  gem 'json', '>= 1.8.1', :platforms => [:jruby, :ruby_18, :ruby_19]
   gem 'mime-types', '~> 1.25', :platforms => [:jruby, :ruby_18]
   gem 'rack-test'
   gem 'rspec', '>= 2.14'
@@ -28,10 +28,4 @@ group :test do
   gem 'simplecov', :require => false
 end
 
-platforms :rbx do
-  gem 'racc'
-  gem 'rubinius-coverage', '~> 2.0'
-  gem 'rubysl', '~> 2.0'
-end
-
 gemspec