Updated openstack/openstack
Project: openstack/cinder  3923e5000c1e2132e8afd85b764aaaadb72b66da
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Storwize driver cleanup

1. Moved Storwize driver into 'ibm' directory and refactored into
   separate files to improve readability and debug-ability. Other IBM
   drivers will be moved into this directory in a separate patch.
2. Errors coming from storage now raise VolumeBackendAPIException,
   and those coming from the driver raise VolumeDriverException.
3. Fixed many pylint errors.
4. Removed any usage of mox from unit tests in favor of mock.

DocImpact

Change-Id: I1696a97279efe834a96b3f3843bc65f0ea6da9cc