allow 2.4.0 to fail

JonRowe · JonRowe · commit b892b289c6ff · 2016-07-06T20:03:26.000+10:00
diff --git a/travis/.travis.yml b/travis/.travis.yml
@@ -38,6 +38,7 @@ matrix:
       env: JRUBY_OPTS='--server -Xcompile.invokedynamic=false'
     - rvm: ruby-head
     - rvm: rbx
+    - rvm: 2.4.0-preview1
   fast_finish: true
 branches:
   only:
