adds Travis Build Status badge (GoogleCloudPlatform#180)

Author: bshaffer

README.md

@@ -2,7 +2,8 @@
 
 A collection of samples that demonstrate how to call Google Cloud services from PHP.
 
-[![Build Status](https://travis-ci.org/GoogleCloudPlatform/php-docs-samples.svg)](https://travis-ci.org/GoogleCloudPlatform/php-docs-samples)
+[![Travis Build Status](https://travis-ci.org/GoogleCloudPlatform/php-docs-samples.svg)](https://travis-ci.org/GoogleCloudPlatform/php-docs-samples)
+![Jenkins Build Status](https://storage.googleapis.com/cloud-samples-tests-php/jenkins-e2e-status.svg)
 [![Coverage Status](https://coveralls.io/repos/github/GoogleCloudPlatform/php-docs-samples/badge.svg?branch=master)](https://coveralls.io/github/GoogleCloudPlatform/php-docs-samples?branch=master)
 
 See our other [Google Cloud Platform github