Support Storage Policy - Rev 2

* Fix API inconsistencies
* Remove hard-coded reseller_prefix = AUTH_
* Remove unused methods from gluster/swift/common/utils.py
  These used to be called from DiskDir earlier.
* Remove hidden configuration option that were related to account
  and container listings and metadata.
* Remove unused and redundant attributes

Signed-off-by: Prashanth Pai <ppai@redhat.com>