fc6c23b753
Convert zaqar jobs to xenial. Newton and newer will run on xenial, older branches on trusty. Let the gate-dsvm-*zaqar run only on trusty and the newer functional/tempest ones on xenial - following the intention of the comments. Mark the gate-dsvm-*zaqar as -nv instead of using special condition to make them non-voting. Change-Id: I8654dbcf02d0c8cf5cc91d993bc9a35010d5758a