qdev_monitor: Simplify error handling in qdev_device_add()

Instead of doing the clean-ups on errors multiple times, introduce
a jump label at the end of the function that can be used by all
error paths that need this cleanup.

Suggested-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
Message-Id: <1509617407-21191-2-git-send-email-thuth@redhat.com>
Reviewed-by: Cornelia Huck <cohuck@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>

qdev-monitor.c

@@ -619,22 +619,22 @@ DeviceState *qdev_device_add(QemuOpts *opts, Error **errp)
 
     /* set properties */
     if (qemu_opt_foreach(opts, set_property, dev, &err)) {
-        error_propagate(errp, err);
-        object_unparent(OBJECT(dev));
-        object_unref(OBJECT(dev));
-        return NULL;
+        goto err_del_dev;
     }
 
     dev->opts = opts;
     object_property_set_bool(OBJECT(dev), true, "realized", &err);
     if (err != NULL) {
-        error_propagate(errp, err);
         dev->opts = NULL;
-        object_unparent(OBJECT(dev));
-        object_unref(OBJECT(dev));
-        return NULL;
+        goto err_del_dev;
     }
     return dev;
+
+err_del_dev:
+    error_propagate(errp, err);
+    object_unparent(OBJECT(dev));
+    object_unref(OBJECT(dev));
+    return NULL;
 }