Fix Travis Build Script

The "after_script" section will be invoked after a successful
build. It clones the remote repository in Openshift, produces the
executable WAR file, removes unrelevant files from the repository,
adds a new git commit and pushes it back to openshift.

For more information, do refer to:
- http://docs.travis-ci.com/user/deployment/custom/
- http://docs.travis-ci.com/user/encrypting-files/
- https://help.openshift.com/hc/en-us/articles/202399740-How-to-deploy-pre-compiled-java-applications-WAR-and-EAR-files-onto-your-OpenShift-gear-using-the-java-cartridges