rgw_admin: flush replicalog entries

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>
rgw: only log (as in ops logging) certain operations

Fixes: #5875
ops logging should (at this point) should only include object
store related operations.

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
Reviewed-by: Josh Durgin <josh.durgin@inktank.com>