GPFS:  Implement volume backup and restore

Add support in gpfs driver for volume backup interface
to backup or restore a volume using backup service
specified in cinder.conf.

Implements: blueprint gpfs-volume-backup
Change-Id: I6f6730bab87c7e7547a66e1b57909f761f87d347
IBM XIV and DS8000 Driver reorganizing (IBM dir)

    * renamed:    cinder/volume/drivers/xiv_ds8k.py
                  -> cinder/volume/drivers/ibm/xiv_ds8k.py
    * updated all references to old xiv_ds8k paths
    * regenerated sample.conf

Change-Id: Iab094c78a0e4eb1753fe8809089ba1337d95e2e0
Partially implements: blueprint ibm-volume-driver-reorg
HP LeftHand Backend assisted volume migrate

This patch implements volume migrate using native LeftHand APIs.

Limitations:
1. Same LeftHand backend
2. Volume cannot be attached
3. Volumes with snapshots cannot be migrated
4. Source and Destination clusters must be in the same management group
5. Volume re-type not supported

Change-Id: I503d5a10ee59db14130c676a5c3a07abf9a2b7af
Implements: blueprint native-lefthand-volume-migrate
Merge "GPFS:  Implement volume backup and restore"
Merge "IBM XIV and DS8000 Driver reorganizing (IBM dir)"
Merge "HP LeftHand Backend assisted volume migrate"