Add rbx to list of allowed failures.

myronmarston · myronmarston · commit fca371bb5812 · 2014-02-10T09:48:45.000-08:00
We're getting odd compile errors from rubinius: rubinius/rubinius#2934
diff --git a/travis/.travis.yml b/travis/.travis.yml
@@ -18,4 +18,5 @@ matrix:
     - rvm: jruby-18mode
     - rvm: jruby-head
     - rvm: ruby-head
+    - rvm: rbx
   fast_finish: true
