Merge pull request #22864 from smithfarm/wip-24774-luminous

luminous: Mimic build fails with -DWITH_RADOSGW=0

Reviewed-by: Kefu Chai <kchai@redhat.com>
Reviewed-by: John Spray <john.spray@redhat.com>
Reviewed-by: David Disseldorp <ddiss@suse.de>

diff --cc CMakeLists.txt
Simple merge

diff --cc ceph.spec.in
Simple merge

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