There may be circumstances when an internal client wishes to modify
container sysmeta that is hidden from the user. It is desirable that
this happens without modifying the put-timestamp and therefore the
last-modified time that is reported in responses to client HEADs and
GETs.
This patch modifies the container server so that a POST will not
update the container put_timestamp if an X-Backend-No-Timestamp-Update
header is included with the request and has a truthy value.
Note: there are already circumstances in which container sysmeta is
modified without changing the put_timestamp:
- PUT requests with shard range content do not update put_timestamp.
- the sharder updates sysmeta directly via the ContainerBroker without
modifying put_timestamp.
Change-Id: I835b2dd58bc1d4fb911629e4da2ea4b9697dd21b
29414ab146