nuke: reset syslog configuration after rebooting
nuke: reset syslog configuration after rebooting

Previously we removed a file and rebooted without syncing, so the file
was never deleted.

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