rgw: send self zonegroup on forward to master

rgw: send self zonegroup on forward to master

When creating a bucket in the secondary zonegroup, the `rgwx-zonegroup`
is mistakenly set to the master zonegroup when forwarding the request.
Instead, it should be set to the secondary zonegroup so that the master
zonegroup creates the bucket for the intended zonegroup rather than
for itself.

Fixes: https://tracker.ceph.com/issues/67610
Signed-off-by: Seena Fallah <seenafallah@gmail.com>
(cherry picked from commit a8e112cf538dfea238a88f52c32da3db35f58c8a)