[ci] Remove oraclejdk8 as no longer valid on xenial platform

hazendaz · mariuszs · commit ca74493a20b9 · 2019-12-30T10:34:40.000+01:00
diff --git a/.travis.yml b/.travis.yml
@@ -1,7 +1,6 @@
 language: java
 
 jdk:
-  - oraclejdk8
   - openjdk8
 
 before_script: ./mvnw install -N
