Merge pull request #54619 from cbodley/wip-rgw-sal-get-stats-async

rgw/sal: clean up read_stats_async() callbacks

Reviewed-by: Daniel Gryniewicz <dang@redhat.com>

diff --cc src/cls/rgw/cls_rgw_client.cc
Simple merge

diff --cc src/cls/rgw/cls_rgw_client.h
Simple merge

diff --cc src/rgw/driver/motr/rgw_sal_motr.cc
Simple merge

diff --cc src/rgw/driver/motr/rgw_sal_motr.h
Simple merge

diff --cc src/rgw/driver/posix/rgw_sal_posix.cc
Simple merge

diff --cc src/rgw/driver/rados/rgw_rados.cc
Simple merge

diff --cc src/rgw/driver/rados/rgw_rados.h
Simple merge

diff --cc src/rgw/driver/rados/rgw_sal_rados.cc
Simple merge

diff --cc src/rgw/rgw_sal.h
Simple merge

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

diff --cc src/test/rgw/test_rgw_lua.cc
Simple merge