Merge pull request #9055 from cbodley/wip-rgw-period-commit-master

rgw: 'period commit' sends to new master zone by default

Reviewed-by: Yehuda Sadeh <yehuda@redhat.com>

diff --cc src/rgw/rgw_admin.cc
Simple merge

diff --cc src/test/cli/radosgw-admin/help.t
Simple merge