watch_notify_stress.py: add ceph flags option
watch_notify_stress.py: add ceph flags option

Signed-off-by: Samuel Just <4c46b94684b338bae1ed5e7e1321718dd75401cc@dreamhost.com>

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