Add volume create from image test

This patch set adds tests for the following policy:

"volume:create_from_image" [0]

Note that this is mutually exclusive with "volume:create" [1]
so multi-policy is not needed for the new test:
test_create_volume_from_image

[0] https://github.com/openstack/cinder/blob/fe69f679369057a7c381178f770bf68d0bc1cee0/cinder/policies/volumes.py#L52
[1] https://github.com/openstack/cinder/blob/4bb00dbcf6af2f140694eb535696f0f6fe3ae80e/cinder/volume/api.py#L210

Change-Id: I27bdefa57ed60e9fb1764a65afec117e86e71cee
1 file changed