documentation typo
documentation typo

Signed-off-by: Loic Dachary <b6eae37fc74638590e3f9030895d42446505d41b@dachary.org>

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