For improving the deletion performance we are shifting the
responsibility to delete the pieces of the object from Uplink to the
Satellite.
BeginDeleteObject was the first call to return the stream ID which was
used for after retrieving the list of segments and then get addressed
order limits for deleting the pieces (of each segment) from the storage
nodes.
Now we want the Satellite deletes the pieces of all the object segments
from the storage nodes hence we don't need anymore to have several
network round trips between the Uplink and the Satellite because the
Satellite can delete all of them in the initial BegingDeleteObject
request.
satellite/metainfo.ListSegments has been changed to return 0 items if
the pointer of the last segment of an object is not found because we
need to preserve the backward compatibility with Uplinks that won't be
updated to the last release and they rely on listing the segments after
calling BeginDeleteObject for retrieving the addressed order limits
to contact the storage nodes to delete the pieces.
Change-Id: I5f99ecf27d62d65b0a062936b9b17581ef692af0
