.travis.yml in signature-0.1.3 vs .travis.yml in signature-0.1.4

@@ -5,7 +5,11 @@
   - 1.9.3
   - jruby-18mode # JRuby in 1.8 mode
   - jruby-19mode # JRuby in 1.9 mode
   - rbx-18mode
   - rbx-19mode
+matrix:
+  allow_failures:
+    - rvm: rbx-18mode
+    - rvm: rbx-19mode
 
 script: bundle exec rspec spec