oracle-java9-set-default (#403)

Author: Peter Bengtsson

.travis.yml

@@ -22,7 +22,7 @@ addons:
   postgresql: "9.5"
   apt:
     packages:
-      - oracle-java8-set-default
+      - oracle-java9-set-default
 
 before_install:
   - curl -O https://artifacts.elastic.co/downloads/elasticsearch/elasticsearch-6.2.1.deb && sudo dpkg -i --force-confnew elasticsearch-6.2.1.deb && sudo service elasticsearch start