iotests/129: Do not check @busy

@busy is false when the job is paused, which happens all the time
because that is how jobs yield (e.g. for mirror at least since commit
565ac01f).

Back when 129 was added (2015), perhaps there was no better way of
checking whether the job was still actually running.  Now we have the
@status field (as of 58b295ba, i.e. 2018), which can give us exactly
that information.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Willian Rampazzo <willianr@redhat.com>
Message-Id: <20210118105720.14824-6-mreitz@redhat.com>

tests/qemu-iotests/129

@@ -70,7 +70,7 @@ class TestStopWithBlockJob(iotests.QMPTestCase):
         result = self.vm.qmp("stop")
         self.assert_qmp(result, 'return', {})
         result = self.vm.qmp("query-block-jobs")
-        self.assert_qmp(result, 'return[0]/busy', True)
+        self.assert_qmp(result, 'return[0]/status', 'running')
         self.assert_qmp(result, 'return[0]/ready', False)
 
     def test_drive_mirror(self):