[utils] update-checkout: Reduce environment variable noise

Author: lorentey

utils/update_checkout/update_checkout/update_checkout.py

@@ -284,8 +284,7 @@ def obtain_additional_swift_sources(pool_args):
     (args, repo_name, repo_info, repo_branch, remote, with_ssh, scheme_name,
      skip_history, skip_tags, skip_repository_list) = pool_args
 
-    env = dict(os.environ)
-    env.update({'GIT_TERMINAL_PROMPT': 0})
+    env = { 'GIT_TERMINAL_PROMPT': 0 }
 
     with shell.pushd(args.source_root, dry_run=False, echo=False):