Fix acloud setup issue with error of no attribute args.update_config.

Bug: 157818682
Test: acloud-dev create --local-instance
Change-Id: I5c6a80507097cedb0f50a00f6d28c8d2d097d584
diff --git a/create/create.py b/create/create.py
index 37b7351..8d2b28e 100644
--- a/create/create.py
+++ b/create/create.py
@@ -166,6 +166,7 @@
     args.host = False
     args.host_base = False
     args.force = False
+    args.update_config = None
     # Remote image/instance requires the GCP config setup.
     if not args.local_instance or args.local_image == "":
         gcp_setup = gcp_setup_runner.GcpTaskRunner(args.config_file)