Updates to support Havana interim version 1.9.1.

The code changes are basically:

  * Apply refactoring in the DiskFile class to use the new DiskWriter
    abstraction

    * Move and rename our diskfile module to match upstream

  * ThreadPools allow us to remove the tpool usage around fsync

  * Update the Ring subclass to support the get_part() method

  * Update to use the 1.9.1 proxy server unit tests

    * Move the DebugLogger class to test.unit

  * Rebuild the Rings to use the new layout

    * Remove backup ring builder files

  * Update spec files to 1.9.1, and tox to use swift 1.9.1

  * Updated version to 1.9.0-0

Change-Id: Ica12cac8b351627d67500723f1dbd8a54d45f7c8
Signed-off-by: Peter Portante <peter.portante@redhat.com>
Signed-off-by: Luis Pabon <lpabon@redhat.com>
Reviewed-on: http://review.gluster.org/5331