rsync for files with metadata containing two spaces in sequence causes exception

When transferring bucket from gs to s3:
`gsutil -qDD rsync gs:// s3://`

for a file with metadata:
```
gsutil ls -L gs:///
...
Content-Disposition: attachment; filename="some text - some text.jpg"
...
```
(notice double space before the dash), getting next error:

```
DEBUG 0815 21:32:36.212000 connection.py] encountered error exception, reconnecting
...
[Errno 10053] An established connection was aborted by the software in your host machine
```

After removing extra space from metadata syncing works.