rgw: RadosBucket::get_bucket_info() updates RGWBucketEnt

rgw: RadosBucket::get_bucket_info() updates RGWBucketEnt

if we construct a RadosBucket without knowing its instance id,
get_bucket_info() will look it up for us and store it in
info.bucket.bucket_id

but RadosBucket::update_container_stats() gets this instance id from
'RGWBucketEnt ent', which wasn't updated by get_bucket_info(). this
causes update_container_stats() to try to read a bucket instance with
empty instance id, which fails with -ENOENT, and the RGWListBucket op
returns uninitialized X-Container-* stats

Fixes: https://tracker.ceph.com/issues/47781
Fixes: https://tracker.ceph.com/issues/47861
Signed-off-by: Casey Bodley <cbodley@redhat.com>
(cherry picked from commit e391e56c7dda24b4a9d6981a5be31fe8b9defd9d)