Merge pull request #2865 from ceph/wip-9479

rgw: send back ETag on S3 object copy

Reviewed-by: Josh Durgin <josh.durgin@inktank.com>

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

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

diff --cc src/rgw/rgw_rest_s3.cc
Simple merge