io: stop incrementing reference in qio_task_get_source

Incrementing the reference in qio_task_get_source is
not necessary, since we're not running concurrently
with any other code touching the QIOTask. This
minimizes chances of further memory leaks.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>

io/task.c

@@ -156,6 +156,5 @@ void qio_task_abort(QIOTask *task,
 
 Object *qio_task_get_source(QIOTask *task)
 {
-    object_ref(task->source);
     return task->source;
 }