Cannot upload gadgets thru the api

```
What steps will reproduce the problem?
See 
https://developers.google.com/google-apps/sites/forum?place=topic%2Fgoogle-sites
-api%2FKdDJ2rV882g%2Fdiscussion

If this bug cannot be fixed, then the api is useless
```

Original issue reported on code.google.com by `seiya.gu...@gmail.com` on 25 Jun 2013 at 1:04
