Update build_blocker to make use of convert_mapping_to_xml()
Update build_blocker to make use of convert_mapping_to_xml()

Change-Id: I104bbfce6b90f8ce62f28b75230ea0e86a5e2295

puppetlabs/jenkins-job-builder,wsoula/jenkins-job-builder,wsoula/jenkins-job-builder,gforcada/jenkins-job-builder,gforcada/jenkins-job-builder,gforcada/jenkins-job-builder,puppetlabs/jenkins-job-builder,wsoula/jenkins-job-builder,puppetlabs/jenkins-job-builder,gforcada/jenkins-job-builder,gforcada/jenkins-job-builder,puppetlabs/jenkins-job-builder,wsoula/jenkins-job-builder