There should be a BLOCK_JOB_READY event with active commit, regardless
of image length. Let's test the 0 length image case, and make sure it
goes through the ready->complete process.
Signed-off-by: NFam Zheng <famz@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>