hmp: Make block_stream set an explicit job ID

A job ID is always required in order to create a block job on a
non-root node. The default ID (obtained with bdrv_get_device_name())
is otherwise empty in this scenario and the job cannot be created.

The HMP block_stream command doesn't set a job ID and therefore it
doesn't allow streaming to intermediate nodes. One solution is to add
an extra parameter to set a job ID. The other solution is to simply
use the node name passed to block_stream as job ID. This won't work
if it's automatically generated (because it contains a '#') but is
otherwise simple enough for all other cases.

This way 'block_stream node3' will create a job with the ID 'node3'
and the good old 'block_stream virtio0' will keep the previous
behaviour and use 'virtio0' for the job ID.
Signed-off-by: NAlberto Garcia <berto@igalia.com>
Signed-off-by: NKevin Wolf <kwolf@redhat.com>

hmp.c

@@ -1570,7 +1570,7 @@ void hmp_block_stream(Monitor *mon, const QDict *qdict)
     const char *base = qdict_get_try_str(qdict, "base");
     int64_t speed = qdict_get_try_int(qdict, "speed", 0);
 
-    qmp_block_stream(false, NULL, device, base != NULL, base, false, NULL,
+    qmp_block_stream(true, device, device, base != NULL, base, false, NULL,
                      false, NULL, qdict_haskey(qdict, "speed"), speed,
                      true, BLOCKDEV_ON_ERROR_REPORT, &error);