Revert of Don't check bucket permissions if --no-auth.

download_from_google_storage.py

Index: download_from_google_storage.py
diff --git a/download_from_google_storage.py b/download_from_google_storage.py
index 4545a95571558aa5160bac866fa31214d865befb..ffdd4ee97893ee7fb6e25e3a9cdc3be01268f838 100755
--- a/download_from_google_storage.py
+++ b/download_from_google_storage.py
@@ -110,7 +110,12 @@
     return (code, out, err)
 
 
-def check_bucket_permissions(base_url, gsutil):
+def check_bucket_permissions(bucket, gsutil):
+  if not bucket:
+    print >> sys.stderr, 'Missing bucket %s.'
+    return (None, 1)
+  base_url = 'gs://%s' % bucket
+
   code, _, ls_err = gsutil.check_call('ls', base_url)
   if code != 0:
     print >> sys.stderr, ls_err
@@ -452,13 +457,10 @@
       parser.error('Output file %s exists and --no_resume is specified.'
                    % options.output)
 
-  base_url = 'gs://%s' % options.bucket
-
   # Check we have a valid bucket with valid permissions.
-  if not options.no_auth:
-    code = check_bucket_permissions(base_url, gsutil, options.no_auth)
-    if code:
-      return code
+  base_url, code = check_bucket_permissions(options.bucket, gsutil)
+  if code:
+    return code
 
   return download_from_google_storage(
       input_filename, base_url, gsutil, options.num_threads, options.directory,