Force download_from_google_storage --config to produce a read-only token

Force download_from_google_storage --config to produce a read-only token

When download_from_google_storage --config is run, it should be implied that
the user just wants to download, not upload.  This change passes the '-r' flag
into gsutil config, which requests a read-only scoped token rather than write
token.  This is saved in ~/.boto.depot_tools so that it doesn't conflict
with a ~/.boto file crated later that may have write permissions.


BUG=

Committed: http://src.chromium.org/viewvc/chrome?view=rev&revision=244276

[Ryan Tseng, 2014-01-10 23:30:00]

This should be a short change, can you take a look?  Thanks.

[M-A Ruel, 2014-01-10 23:31:59]

lgtm

https://codereview.chromium.org/135153002/diff/1/download_from_google_storage.py
File download_from_google_storage.py (right):

https://codereview.chromium.org/135153002/diff/1/download_from_google_storage...
download_from_google_storage.py:366: os.path.expanduser('~/.boto.depot_tools'))
Note that we've seen '~' expansion issues on Windows.

That said, this needs to be debugged anyway, it's just FYI in case a problem
arise.

[Ryan Tseng, 2014-01-10 23:34:21]

https://codereview.chromium.org/135153002/diff/1/download_from_google_storage.py
File download_from_google_storage.py (right):

https://codereview.chromium.org/135153002/diff/1/download_from_google_storage...
download_from_google_storage.py:366: os.path.expanduser('~/.boto.depot_tools'))
On 2014/01/10 23:32:00, M-A Ruel wrote:
> Note that we've seen '~' expansion issues on Windows.
> 
> That said, this needs to be debugged anyway, it's just FYI in case a problem
> arise.

Didn't know that.  Line 64/65 would also need to be fixed if any problems arise.
 The default place for a windows boto file should be in $HOME\.boto iirc.

[commit-bot: I haz the power, 2014-01-10 23:34:28]

CQ is trying da patch. Follow status at
https://chromium-status.appspot.com/cq/hinoka@google.com/135153002/1

[commit-bot: I haz the power, 2014-01-10 23:36:26]

Change committed as 244276