Add a short hostname to travis conf, so that openjdk doesn't crash and add headless mode to the test run.
Add a short hostname to travis conf, so that openjdk doesn't crash and add headless mode to the test run.

git-svn-id: https://svn.apache.org/repos/asf/jmeter/trunk@1733112 13f79535-47bb-0310-9956-ffa450edef68

Former-commit-id: fd3ae0b08a8098fb13c566c0c5cee6f045f0fec1
ham1/jmeter,ham1/jmeter,benbenw/jmeter,apache/jmeter,benbenw/jmeter,benbenw/jmeter,etnetera/jmeter,etnetera/jmeter,apache/jmeter,etnetera/jmeter,ham1/jmeter,etnetera/jmeter,benbenw/jmeter,ham1/jmeter,apache/jmeter,etnetera/jmeter,apache/jmeter,apache/jmeter,ham1/jmeter