rgw: Fix swift object expiry not deleting objects

rgw: Fix swift object expiry not deleting objects

In cls_timeindex_list() though `to_index` has expired for a timespan, the marker is set for a subsequent index during the time boundary check.
This marker is further returned to RGWObjectExpirer::process_single_shard(), where this out_marker is trimmed from the respective shard,
resulting in a lost removal hint and a leaked object.

Fixes: http://tracker.ceph.com/issues/22084
Signed-off-by: Pavan Rallabhandi <PRallabhandi@walmartlabs.com>