Clee/getinfoproto

@ormsbee get_info and upload. 
The database error message isn't necessary. You can also combine the internal error cases like:

```python
try:
    v = Video.objects.get(edx_video_id=edx_video_id)
    result = EncodedVideoSetSerializer(v)
except Video.DoesNotExist:
    error_message = u"Video not found for edx_video_id: {0}".format(edx_video_id)
    raise ValVideoNotFoundError(error_message)
except Exception:
    error_message = u"Could not get edx_video_id: {0}".format(edx_video_id)
    logger.exception(error_message)
    raise ValInternalError(error_message)
```