Add no_auth flag to skip auth checking for buckets that don't require it. Also fix tests

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 bbb9e64f3b08865eac683a374e5a2006be7a636e..99636089505687677cd8097cd6a17f6a76fd1e43 100755
--- a/download_from_google_storage.py
+++ b/download_from_google_storage.py
@@ -297,7 +297,10 @@ def main(args):
                     help='Alias for "gsutil config".  Run this if you want '
                          'to initialize your saved Google Storage '
                          'credentials.')
-  parser.add_option('-p', '--platform', 
+  parser.add_option('-n', '--no_auth', action='store_true',
+                    help='Skip auth checking.  Use if its known that the '

[ghost stip (do not use), 2013/11/19 19:32:37]

it's

+                         'target bucket is a public bucket.')
+  parser.add_option('-p', '--platform',
                     help='A regular expression that is compared against '
                          'Python\'s sys.platform. If this option is specified, '
                          'the download will happen only if there is a match.')
@@ -365,7 +368,8 @@ def main(args):
                    % options.output)
 
   # Check we have a valid bucket with valid permissions.
-  base_url, code = check_bucket_permissions(options.bucket, gsutil)
+  if not options.no_auth:
+    base_url, code = check_bucket_permissions(options.bucket, gsutil)
   if code:
     return code