Move nova-cells-v1 job to the experimental queue

Nova is moving the nova-cells-v1 job to its experimental
queue so we should do the same in Tempest.

Depends-On: https://review.openstack.org/623538

Change-Id: I277f3a4bea69501ea4c07118c552343d5ea38f6a
Related-Bug: #1807407
1 file changed