Fix volume transfers rbac test

Following recent change in Tempest [0], volume transfers
functionality has been moved out of volumes client into a volume
transfers client.

This patch makes the appropriate change in Patrole to work
with the new change to Tempest.

[0] https://review.openstack.org/#/c/438006/

Change-Id: Ie1c4b6a2801f10c8e83f6d3f88fe0364d69317fa
Related-Change: Ia85bcfbadbff4f7c594dc5631ecdd595c5d275f3
1 file changed