ceph: disable logrotate
ceph: disable logrotate

This screwed up the log archival step at the end, and generally makes a
mess of automated runs.

Fixe: #5451

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