Increase test coverage for cinder.image.image_utils

Add new tests for:
	convert_image()
	qemu_img_info()
	fetch_to_raw()
	fetch_verify_image()
	upload_volume()

Change-Id: Ie69af94433b4c61a493d6c38b4c9439a367f7af8
Remove _create_volume function from several tests

Remove _create_volume function from
- db/test_transfers.py
- api/contrib/test_backups.py
- test_gpfs.py
- test_volume_transfer.py
- test_volume.py
And use create_volume from tests/utils.py instead

Change-Id: I446220d0cfaa2850a5262a968ed35b7827b90a03
Fixes bug to allow for encrypted volume deletion

delete_key in cinder/volume/api.py was called with incorrect parameters.
The error prevented encrypted volumes from being deleted, but the fix
has been applied and unittests written to prove the functionality.

Change-Id: I3b93da84f97efe2a3afa057907bbfa10336eb9de
Implements: blueprint encrypt-cinder-volumes
Merge "Increase test coverage for cinder.image.image_utils"
Merge "Remove _create_volume function from several tests"
Merge "Fixes bug to allow for encrypted volume deletion"