Fixed build status badge to refer to master branch.

Author: mboersma

README.md

@@ -2,7 +2,7 @@
 
 Deis is a Django/Celery API server, Python CLI and set of [Chef cookbooks](https://github.com/opdemand/deis-cookbook) that combine to provide a Heroku-inspired application platform for public and private clouds.  Your PaaS. Your Rules.
 
-[![Build Status](https://travis-ci.org/opdemand/deis.png)](https://travis-ci.org/opdemand/deis)
+[![Build Status](https://travis-ci.org/opdemand/deis.png?branch=master)](https://travis-ci.org/opdemand/deis)
 [![Coverage Status](https://coveralls.io/repos/opdemand/deis/badge.png?branch=master)](https://coveralls.io/r/opdemand/deis?branch=master)
 
 ![Deis Graphic](https://s3-us-west-2.amazonaws.com/deis-images/deis-graphic.png)