Use jdk8 to run CI

Author: Ajay Kannan

.travis.yml

@@ -1,7 +1,9 @@
 language: java
 jdk:
-  - oraclejdk7
-env: GOOGLE_APPLICATION_CREDENTIALS=$TRAVIS_BUILD_DIR/service-account.json
+  - oraclejdk8
+env:
+  - GOOGLE_APPLICATION_CREDENTIALS=$TRAVIS_BUILD_DIR/service-account.json
+  - GCLOUD_PROJECT=cloud-samples-tests
 before_install:
   - openssl aes-256-cbc -K $encrypted_99d8b304f94b_key -iv $encrypted_99d8b304f94b_iv -in service-account.json.enc -out service-account.json -d