Fix: Rubinius build, lock at rbx-2.2.10, remove platform :rbx block.

.travis.yml

@@ -8,7 +8,7 @@ rvm:
   - 2.0.0
   - 1.9.3
   - jruby-19mode
-  - rbx-2
+  - rbx-2.2.10
   - jruby-head
   - ruby-head
 

Gemfile

@@ -1,10 +1,6 @@
 source 'http://rubygems.org'
 
-platforms :rbx do
-  gem 'rubysl'
-  gem 'rubinius-developer_tools'
-  gem 'racc'
-end
+gemspec
 
 group :development do
   gem 'pry'
@@ -14,8 +10,6 @@ group :development do
   gem 'guard-rspec', '~> 4.3.1', require: false
 end
 
-gemspec
-
 group :test do
   # ActiveSupport required to test compatibility with ActiveSupport Core Extensions.
   gem 'activesupport', require: false