ovirt-engine_3.6_check-patch-el7-x86_64 job failing and stuck

This job is failing with this error *09:37:48* umount: /var/lib/mock/epel-7-x86_64-d496d3daa673001f46dbbd9addf9ba1b/root/home/jenkins/workspace/ovirt-engine_3.6.1_build-artifacts-el7-x86_64/ovirt-engine: target is busy*09:37:48* (In some cases useful info about processes that*09:37:48* use the device is found by lsof(8) or fuser(1).) and the rest of the incoming jobs are stuck http://jenkins.ovirt.org/job/ovirt-engine_3.6_check-patch-el7-x86_64/