qtest/ahci: add halted dma test

If we're going to test the migration of halted DMA jobs,
we should probably check to make sure we can resume them
locally as a first step.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Message-id: 1430417242-11859-9-git-send-email-jsnow@redhat.com
