Test on jruby-head otherwise jruby is in 1.9 mode.

ioquatix · ioquatix · commit 6368d2b17f54 · 2017-03-09T22:53:42.000+13:00
diff --git a/.travis.yml b/.travis.yml
@@ -9,7 +9,7 @@ rvm:
   - 2.3.2
   - 2.4.0
   - rbx
-  - jruby
+  - jruby-head
 matrix:
   allow_failures:
     - rvm: rbx
