Update class HipChat to use convert_xml()
Update class HipChat to use convert_xml()

Change-Id: I525955073483e713e634bd1591b1344754fba289

wikimedia/integration-jenkins-job-builder,gforcada/jenkins-job-builder,phinexus/jenkins-job-builder,gforcada/jenkins-job-builder,phinexus/jenkins-job-builder,rsig/jenkins-job-builder,puppetlabs/jenkins-job-builder,phinexus/jenkins-job-builder,puppetlabs/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,wikimedia/integration-jenkins-job-builder,rsig/jenkins-job-builder,OSSystems/jenkins-job-builder,rsig/jenkins-job-builder,wsoula/jenkins-job-builder,OSSystems/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,puppetlabs/jenkins-job-builder,rsig/jenkins-job-builder,phinexus/jenkins-job-builder,gforcada/jenkins-job-builder,wikimedia/integration-jenkins-job-builder,puppetlabs/jenkins-job-builder,wsoula/jenkins-job-builder,wsoula/jenkins-job-builder,gforcada/jenkins-job-builder,phinexus/jenkins-job-builder,OSSystems/jenkins-job-builder,OSSystems/jenkins-job-builder,gforcada/jenkins-job-builder,wsoula/jenkins-job-builder