Only upload node with gsutil in update_node.py if --upload is passed. (#1472)

This allows running the script locally.

Is there some kind of automated script that needs a matching update, or
was this always run manually?

scripts/update_node.py

@@ -13,6 +13,7 @@ direcotry.
 
 import urllib.request
 import subprocess
+import sys
 import os
 import shutil
 
@@ -46,6 +47,7 @@ for suffix in suffixes:
       subprocess.check_call(['zip', '-rq', filename, dirname])
       shutil.rmtree(dirname)
 
+    if '--upload' in sys.argv:
       upload_url = upload_base + filename
       print('Uploading: ' + upload_url)
       cmd = ['gsutil', 'cp', '-n', filename, upload_url]