smoke: specify fs on each run

Signed-off-by: Sage Weil <sage@inktank.com>
smoke: add some rados osd thrashing test

ec, caching, snaps

Signed-off-by: Sage Weil <sage@inktank.com>
smoke: add a mon thrash test

Signed-off-by: Sage Weil <sage@inktank.com>