update travis config

Author: monkstone

.travis.yml

@@ -2,22 +2,9 @@ sudo: false
 
 language: ruby
 
-bundler_args: --without production
-
-addons:
-  apt:
-    packages:
-      - oracle-java8-installer
-
 rvm: 
-  - jruby-head
+  - jruby-9.1.1.0
 
 jdk:
   - oraclejdk8
 
-env:
-  - JRUBY_OPTS="$JRUBY_OPTS" JAVA_OPTS="-Djruby.version=$JRUBY_VERSION"
-
-before_script:
-  - export JRUBY_OPTS="-Xcext.enabled=false -Xcompile.invokedynamic=false"
-