Add block_job_cancel, which stops an active block streaming operation.
When the operation has been cancelled the new BLOCK_JOB_CANCELLED event
is emitted.
Signed-off-by: NStefan Hajnoczi <stefanha@linux.vnet.ibm.com>
Acked-by: NLuiz Capitulino <lcapitulino@redhat.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>