qdev: Free opts on failed do_device_add

If the device can't be created, don't leak the QemuOpts and release the id of
the device that should have been added by the failed device_add.
Signed-off-by: NKevin Wolf <kwolf@redhat.com>
Signed-off-by: NAnthony Liguori <aliguori@us.ibm.com>

hw/qdev.c

@@ -749,8 +749,11 @@ void do_device_add(Monitor *mon, const QDict *qdict)
 
     opts = qemu_opts_parse(&qemu_device_opts,
                            qdict_get_str(qdict, "config"), "driver");
-    if (opts && !qdev_device_help(opts))
-        qdev_device_add(opts);
+    if (opts) {
+        if (qdev_device_help(opts) || qdev_device_add(opts) == NULL) {
+            qemu_opts_del(opts);
+        }
+    }
 }
 
 void do_device_del(Monitor *mon, const QDict *qdict)