travis: Change from after_success script to travis deploy

.travis.yml

@@ -21,8 +21,14 @@ script:
   - ./test
   - ./test-functional
 
-after_success:
-  - if [[ "$TRAVIS_GO_VERSION" == "1.5.3" && "$TRAVIS_PULL_REQUEST" == "false" && "$TRAVIS_BRANCH" == "master"  ]]; then ./build-docker-push ;fi
+deploy:
+  provider: script
+  script: build-docker-push
+  skip_cleanup: true
+  on:
+    branch: master
+    go: '1.5.3'
+    condition: "$TRAVIS_PULL_REQUEST = false"
 
 notifications:
   email: false