Make rbd.libvirt_info parent class compatible

Rbd.libvirt_info function definition misses hypervisor_version argument added in change:
https://review.openstack.org/32379

Closes-Bug: #1233188
Change-Id: Ib68d743e783af0f6d82d2ba180869ee642e86050
(cherry picked from commit 7a34be0ec0cd0cb9555fe64ff6c486faae1ae91d)
Merge "Make rbd.libvirt_info parent class compatible" into stable/havana