Remove JDK 9 build from Travis CI

acogoluegnes · acogoluegnes · commit bd38b2e4891d · 2018-10-17T15:31:46.000+02:00
JDK 9 is no longer supported and there's a multi-JDK test pipeline for
RabbitMQ-related Java projects.
diff --git a/.travis.yml b/.travis.yml
@@ -4,7 +4,6 @@ sudo: required
 language: java
 jdk:
   - oraclejdk8
-  - oraclejdk9
 
 notifications:
   email: acogoluegnes@pivotal.io
