Add RHEL support to teuthology
Add RHEL support to teuthology

Fix #4946
Signed-off-by: Warren Usui <021fe6d8989d7bdb08c8700d8c426ea80a140097@inktank.com>

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