Skip ServerShowV254Test.test_rebuild_server in cells v1 job
Skip ServerShowV254Test.test_rebuild_server in cells v1 job

This adds yet another rebuild test to the blacklist for the
cells v1 job. Rebuild status updates are racy in the cells v1
job because of the async status updates.

Change-Id: I42f08ee2a7282c9cad761bbe0daa111e79678791
Related-Bug: #1709985

klmitch/nova,rahulunair/nova,mahak/nova,mikalstill/nova,gooddata/openstack-nova,klmitch/nova,gooddata/openstack-nova,klmitch/nova,mahak/nova,gooddata/openstack-nova,gooddata/openstack-nova,rahulunair/nova,rahulunair/nova,mikalstill/nova,openstack/nova,mahak/nova,openstack/nova,mikalstill/nova,klmitch/nova,openstack/nova