rgw/d4n: removing code that writes object entry to the

rgw/d4n: removing code that writes object entry to the
object directory in redis

Objects were being written to the directory for bucket listing
but another data structure needs to be used that allows for
ordered listing indexed by a bucket name/ id, hence removing
the entries that do not serve this purpose (they also add to the
number of calls to the redis server).

Signed-off-by: Pritha Srivastava <prsrivas@redhat.com>