nuke-on-error: only unlock if this run locked the machines
nuke-on-error: only unlock if this run locked the machines

ivotron/teuthology,michaelsevilla/teuthology,ceph/teuthology,tchaikov/teuthology,caibo2014/teuthology,yghannam/teuthology,robbat2/teuthology,yghannam/teuthology,dmick/teuthology,t-miyamae/teuthology,ivotron/teuthology,zhouyuan/teuthology,dreamhost/teuthology,t-miyamae/teuthology,michaelsevilla/teuthology,robbat2/teuthology,ktdreyer/teuthology,ktdreyer/teuthology,SUSE/teuthology,SUSE/teuthology,ceph/teuthology,zhouyuan/teuthology,dreamhost/teuthology,caibo2014/teuthology,dmick/teuthology,tchaikov/teuthology,SUSE/teuthology,dmick/teuthology