rgw (test): remove some warnings

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
rgw: remove test placement info

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>
rgw: automatic pool creation for placement pools

With the new pools configuration, now we auto create the
pools when needed (through bucket creation). Also, make
sure only to configure default placement in zone structure,
if old config hasn't been done yet.

Signed-off-by: Yehuda Sadeh <yehuda@inktank.com>