`poosh sync --help` should not sync

This was an unfortunate surprise
```
11:34 $ poosh sync --help
[updated] s3-us-west-2.amazonaws.com/www-mysite-com/index.html
[created] s3-us-west-2.amazonaws.com/www-mysite-com/404.html

Matched files: 5 (381 kB), 100%.
Uploaded files: 2 (3.57 kB), done.
Deleted remote files: 0 (0 B), done.
1 creation, 1 update, 0 deletions, 3 skips.
Elapsed time: 2 seconds.
```