rgw: In a multi-site environment, deleting the key from the bucket list operation will cause the object's key to be permanently lost.

[WeiGuo Ren <rwg1335252904@gmail.com>]

In a multi-site synchronization environment, the bucket full sync
process will send a bucket list request to the remote, but the remote
execution of the bucket list operation is likely to delete the object
key.
for example:
t1 object upload-start [rgw_bucket_dir_entry.exists =false] （put obj）
t2 list bucket opreate start find 'rgw_bucket_dir_entry.exists
=false'，and get_obj_state() return noevent. (list bucket)
t3 object upload-end ，[rgw_bucket_dir_entry.exists =true],(put obj)
t4 list bucket remove object key because t2.(list bucket)
I wonder if it is possible to add a timestamp to rgw_bucket_dir_entry,
if you want to delete the key, to determine whether it expires and
delete it.